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Gallery, Projects and General => Project Logs => Topic started by: bogstandard on December 03, 2009, 06:35:01 AM

Title: Swingup external threading tool
Post by: bogstandard on December 03, 2009, 06:35:01 AM
This all started a bit back when I saw the post by Andy here

http://madmodder.net/index.php?topic=1276.msg23777#msg23777

From an original idea by Mike Cox.

I will be using his great idea and putting a few of my own mods onto it.

It has been nagging at the back of my mind since, and if I could get it to work satisfactorily, I think I will be happy having a tooling holder that will do just external threads, as internal threads are so few and far between, I can easily cope with the normal methods of doing them.
Having picked up on a few pointers, like John Stevenson's issue of being able to get close enough to the chuck, I think I have a design in my head that will work and allay a few fears in that department.

This would have been posted last night, if I hadn't had a late night gumbeating with Darren on Skype. How time flies.

Just a warning, I have nothing down on paper for this one, as I am designing and making as I go along, so please don't ask for sketches just yet. I will be showing how it progresses gradually from raw materials to hopefully a fully operational bit of tooling, warts and all.
I make no excuses about using the tooling I have, at times like this, I use whatever is available to me. If you ain't got it, you ain't got it, full stop, no arguments.

So belt and braces on, hitch up your pants, away we go.

A quickie order to Chronos (if you could ever say Chronos was quick) had a couple of cheapo 10mm square brazed tip threading tools in my grubby claws.

http://www.chronos.ltd.uk/acatalog/TWINW_PACKS_OF_BRAZED_TCT_THREADING_TOOLS.html

I have thought ahead a bit on this part, and almost any shape or size of threading tooling can be used with a slight mod. More on that later.

The next bit was a toolholder for me to copy from, and a lump of cast steel that was originally cut up for making the retracting toolpost out of. The square is there just for checking things out with. I have a set of engineers squares specifically for bench only use, and others that are used around the machines, they are so cheap, it pays to do this sort of thing, a 'best' set, and general working ones.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup01.jpg)


The very first thing I do is check my machines out, it only takes a few minutes, and it saves you chasing your own tail feathers trying to get things square and flat.

Set up the tramming tool first. The collet is loose, and I made sure I had double zero on pressing against the table top.

Making a tramming tool is here.

http://madmodder.net/index.php?topic=822.0

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup02.jpg)


Lock the tool into the collet and take a reading, as you can easily see, it is a little out (BTW these are metric dials, so those using imperial, this reading would look a little on the high side. This is about 0.006" in imperial money). It is dead easy to knock the tram out on your machine, even one as heavy as mine. So it always pays to check before starting an important project.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup03.jpg)


A couple of minutes later, the tram was back to spot on.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup04.jpg)


Next, the vice was checked for being square to the table run.

Ready to go.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup05.jpg)


First job was to flatten and square up the block on all faces.
I tried to use my preferred method, the flycutter, but it was struggling getting into the metal.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup06.jpg)


Then tried it with some coolant, no joy, it was still not happy.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup07.jpg)


So out came the heavy brigade, and that went thru it as though it didn't exist.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup08.jpg)


The ends needed to be squared up next. The cutter wasn't long enough to do the whole face in one go.
So I went as deep as I could, as long as it went some way past centre. The block was then flipped over and the backstop set onto the centre of the material, onto the freshly cut face.
It was then a matter of doing a cut across, rotating the bar around the x axis and skimming off the uncut bit. Then flip the block over and do the same to the other end.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup09.jpg)


The block was soon square and flat on all points of the compass.
I haven't measured up the block, as long as it is somewhere near to what I want, it can be fine tuned to size later.
I now needed to get the dovetail in so that it can be mounted to the toolpost.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup10.jpg)


I did a quickie measure up of the original, and marked up roughly where I wanted the mounting to be. As you can see, it isn't central to the block. You will see why later.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup11.jpg)


The area that I marked up is where the piston on the toolpost operates, and is on a different level to where the dovetail goes, so this depth is rather important.
The marked up area was cut away until the 'lines were split'.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup12.jpg)


The depth was then finely cut down to a certain figure.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup13.jpg)


Which just so happened to be the same as the original holder.
If you go too far astray on the depth, you can find that you can have trouble getting the holder locked on tight to the toolpost, especially if you go a little too deep. The critical part is the distance between each dovetail face, and I will be showing that sometime soon.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup14.jpg)


It is now time to break out the secret weapon.
I bought this 60 degree HSS dovetail cutter over 20 years ago, to make a new topslide for a small Myford, from the same chappie I get my specialist cheapo tooling at the shows nowadays. It has cut many dozens of dovetails since, it is the best 5 squid I have ever spent on a cutting tool.
Isn't it funny how you can easily get attached to a favourite bit of kit. I have brand new ones waiting in the wings if ever this one decides to retire, but it will still be used until it decides to do so.
The cutter was 'touched on' the bottom face, then lifted 0.020" upwards. This is to allow the correct working of a dovetailed slot.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup15.jpg)


They make a funny 'rattling' noise as they cut, and you can soon pick up when it needs to have the cut reduced and/or a squirt of oil.

There is a bit of a secret to using dovetail cutters, you start off with a fairly deep cut, in my case about 0.025" @ 800 RPM and as the cuts gradually work their way up the cutting edge, so I gradually reduce the load on the cutter by adjusting the depth of cut and speed. The last cut I took was 0.005" @ 500 RPM. Of course those figures were my own for this size of dovetail and material type. On brass or ali, the speeds would be higher and the depths deeper.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup16.jpg)

So that is as far as I got last night.
If I don't overstay my power nap this afternoon, I will see if I can get a bit more done later.


Bogs
Title: Re: Swingup external threading tool
Post by: Darren on December 03, 2009, 07:06:08 AM
Very nice start .... as usual ... and comprehensive with all the links  :thumbup:

That reminds me .... off to the shed I go ... later  :ddb:
Title: Re: Swingup external threading tool
Post by: NickG on December 03, 2009, 07:26:03 AM
Nice start John. This will be interesting and provide me some pointers if I do a QCTP. Gone are the days when I get £100 christmas persents like that so I think I will have to make one. :lol:

What is the purpose of the 20 thou relief again?

Nick
Title: Re: Swingup external threading tool
Post by: bogstandard on December 03, 2009, 07:45:32 AM
The dovetails don't need to be in full contact across the bottom face as it would just be too much friction, so by relieving the area and only having it running on the smaller outside face areas, friction is dramatically reduced.

If you look at the dovetails on your machines, you should see the same effect being used.

You can do the same thing by putting a recess in the middle of the male dovetail instead of the female.


John
Title: Re: Swingup external threading tool
Post by: NickG on December 03, 2009, 08:01:11 AM
Oh right, I see. Thanks.
Title: Re: Swingup external threading tool
Post by: andyf on December 03, 2009, 08:17:50 AM
As I said in the post to which you linked, Bogs, the idea is not mine. Credit where credit is due, which is to Mike Cox. By coincidence, he has an article in this month's Model Engineers' Workshop describing a nice way of securing his Norman-style toolpost so he can fit two tools into each block rather than just one.

Andy
Title: Re: Swingup external threading tool
Post by: bogstandard on December 03, 2009, 08:42:45 AM
Thanks for that Andy, I always try to give the due recognition that they deserve for their hard work, as you will see in a lot of my posts. Unfortunately, by what you showed, I didn't know from whom it had originated from, and in a few minutes time, the above post will be changed to give all due recognition.

One thing I really hate is people using others ideas and making out they are their own.

It is for that reason I have gone to watermarking my pics, I know it is only very basic security, but the number of sites I have been to that use them without any recognition or permission at all astounds me.

I did get my own back on one chappie on the HMEM site that basically had almost a complete article of mine on his site about my making of an own design turbine. I deleted the youtube vids to all the links he gave. The article as far as I know is still there with no vids.

Only last week a member on here asked for permission to use my Paddleducks book on his site. No problems at all, as long as no one makes money out of it.

Thanks again

John
Title: Re: Swingup external threading tool
Post by: andyf on December 03, 2009, 09:28:38 AM
Entirely agree, Bogs. Even when people have put their ideas their ideas into the public domain, as Mike Cox did with this one on the 7x12 Mini-lathe Yahoo Group along with pics of his finished product, it's only fair that proper attributions should be given. Once you have finished the device, I'll invite him to view this thread, provided your report on how well it works is  :thumbup: and not  :bang:

Andy
Title: Re: Swingup external threading tool
Post by: Gerhard Olivier on December 03, 2009, 03:25:22 PM
Nice work Bogs

Cant wait to see where your taking this one.

Gerhard
Title: Re: Swingup external threading tool
Post by: bogstandard on December 04, 2009, 05:27:06 PM
I got overpowered by heavy eyelids yesterday, so I had a fairly good session today.

I would just like to point out that because I work in both metric and imperial all the time, you will most probably notice that I will be swapping and changing between the two, and will be talking measurements in either. This is just the way I work when I am winging it, and if I pick up an imperial mic, that will be used, even though I am might be cutting in metric at the time. At the very end, when it is all finished, then we can measure up in one or the other.

So lets get on, work to do.

I left it last time with just one side cut, so the first thing that I did was to cut the other side to the same sideways penetration as the other. I am still a way off having the correct width for the dovetail, and because I am copying a known good one, it makes it dead easy, because you can just cut to the right width and guarantee it will fit, whereas normally, you will have to keep trying it onto the male dovetail.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup17.jpg)


So, what is the right width, and how do you measure it.
I grab a couple of small bars of round stock, as long as they touch both side and bottom of the cut dovetail, then it will do.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup18.jpg)


Pop them into the original like shown, and measure the distance between the two. Write it down on a bit of paper.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup19.jpg)


Then do the same with the one that is being machined. Write it down, underneath the reading you wrote down before.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup20.jpg)


Subtract the lower from the upper and divide the result in two. That will be how much you machine out from each side.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup21.jpg)


Job done.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup22.jpg)


Before taking it off the mill, I decided to chamfer all the square edges. This is a true 45 deg milling cutter, not a countersink, which you could use, but this gives much faster and better results.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup23.jpg)


As I said, it will fit and lock on if you get your measuring and machining right.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup24.jpg)


So that piece can be put to one side for now, and a start made on the toolholder swinging bit.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup25.jpg)


Mark out what I want to do with it, but the maching will all be done from datum points, not the markings, they are there as a safety precaution.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup26.jpg)


The first job was to cut out the tool recess.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup27.jpg)


Then drill out the pivot hole to 10mm.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup28.jpg)


Now because this hole has been drilled from this side, I need to make a datum that is perfectly square to the hole, so I took a very shallow cut across the face with a flycutter.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup29.jpg)


Now when it was turned over and put onto parallels, after this side is reduced down to the thickness I want, the hole will also be perfectly square to this face as well.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup30.jpg)


This is it after the thicknessing exercise. You can start to see what I am doing.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup31.jpg)


The holder was marked up again, and was given a bit of profiling.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup32.jpg)


Not quite there, but you can see how it will fit onto the block.
You might ask why the pivot point has been dropped to lower than the centreline of the cutter.
Anyone who has dealt with swept wing aircraft will understand what is called wingtip growth, where when it turns going forwards, because of the chord length of the wing, the tip starts to protrude further out.
It is the same effect on this, by putting the pivot point as low as possible in relation to the tip, when the tip rises, it will in fact make the tip retract from the job slightly, whereas if higher than the tip, the tip would move towards the job. Only tiny amounts, but everything helps in situations like this.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup33.jpg)

I gave up at that, I was hurting a little bit too much, so if all goes well, I will get back to it tomorrow.
Besides, I dropped the damned drill chuck when taking it out of the quill onto my little finger, and it is time I went to get a bit of pampering.

Bogs
Title: Re: Swingup external threading tool
Post by: spuddevans on December 04, 2009, 06:15:32 PM
I'm following this with keen interest as i do most of my threading on the lathe by single pointing. This is yet another item that is added to an ever growing list of mods to be made to my lathe.

oh well, better to have plenty to do than to stand in the workshop wondering what to do.

Tim
Title: Re: Swingup external threading tool
Post by: bogstandard on December 05, 2009, 02:21:48 AM
Tim,

Don't be too hopeful, this is experimental, using a few known tricks that I know work. In theory it should work just fine, in practice, things can have a totally different outcome.

It is later, when I get to the very fine tuning that problems sometimes occur.

If it does work, then there are maybe thousands of newbies out there where it could help to solve their problems and make it easier for them to screwcut, if it doesn't, back to the drawing board.


John
Title: Re: Swingup external threading tool
Post by: bogstandard on December 05, 2009, 01:13:14 PM
Only a very short post today.

I decided that I needed to get the main block cut out to see where I need to hack away at to give me clearance and access to the bits.

The first job was to get the main channel cut out.
Using tungsten cutters, this material just gets swept away, and very little heat is generated, so no suds needed, and unlike cast iron, you don't get dirty.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup34.jpg)


Once the main cutout had been done, I reduced what was left of the main block down to the thickness I wanted.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup35.jpg)


The main block heavy machining is now basically finished, it just needs lots of holes drilling in it now.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup36.jpg)


This is how the swinging bit will fit in.
The small thin file in there is to let me see what gaps I have to play with. The only point that the swing fitting will be in main contact with the block is at the back pivot point. The three lower faces, bottom and two sides will be controlled with limit screws, and by doing it that way, should allow the tool to be used for both right and left hand threading, as all cutting pressures will be taken by them rather than the pivot when in the cutting stage.
It also means that by supporting the swing part away from the main block, it shouldn't jam up or get put out of cutting alignment if a tiny bit of swarf gets in there.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup37.jpg)



Bogs
Title: Re: Swingup external threading tool
Post by: chuck foster on December 05, 2009, 08:01:32 PM
looking good bogs.................i like to see tools being produced in the home shop.  :thumbup:

chuck  :wave:
Title: Re: Swingup external threading tool
Post by: Darren on December 06, 2009, 12:01:31 AM
You do get a good finish on that mill John  :dremel:
Title: Re: Swingup external threading tool
Post by: NickG on December 06, 2009, 03:36:30 AM
Bogs, great write up and that certainly looks a lot different to the block of metal you started with. A lot of work in that.  :bow:

Nick
Title: Re: Swingup external threading tool
Post by: bogstandard on December 06, 2009, 04:01:17 AM
Chuck,

I am renowned for NOT making shop tooling, especially if it can be bought cheaply. But when an idea like this does get into my head, and you can't buy it from anywhere, I love running with it to a conclusion.

In this case, although it does look to be a little complicated, mainly because I made it to fit my own toolpost, if it works when finished, I have no doubts that the average Joe in a workshop could fairly easily replicate it in a size and guise that would work for them.

I am struggling at the moment trying to fulfill the two comments criteria placed upon the retracting toolpost and this swing type, namely to be able to cut left hand threads (swing), and the most difficult one, by John Stevenson, to get the cutting tool close enough to the chuck without the holder hitting (retracting). The left hand threading is easy, unfortunately, the easy fix for that compromises the getting close problem.
 
I will have to see just how much material I can cut away to achieve it, and still retain enough rigidity in the tool. Luckily, single point threading, if done correctly, doesn't require massive cutting loads.


Darren,

Thanks, but of course it is all mainly due to machine rigidity and sharp cutting tools, which for the first one, most people can't achieve to a high degree. I am very lucky in that department.

It is a shame that flash photography shows up all the minute machining marks, that in real life, the surfaces are like silk, and a quick once over with some W&D, the marks will disappear completely.


John
Title: Re: Swingup external threading tool
Post by: andyf on December 06, 2009, 04:54:45 AM
Quote
I am struggling at the moment trying to fulfill the two comments criteria placed upon the retracting toolpost and this swing type, namely to be able to cut left hand threads (swing), and the most difficult one, by John Stevenson, to get the cutting tool close enough to the chuck without the holder hitting (retracting). The left hand threading is easy, unfortunately, the easy fix for that compromises the getting close problem.

Bogs, maybe an arrangement as shown below (top view) with the pivot in the middle of a longer toolholder, would let the thing get close to the chuck. There would be considerable overhang forward of the pivot, though, and consequent leverage.

Andy
 
(http://i689.photobucket.com/albums/vv257/andyf1108/Swinguptoolholder.jpg)
Title: Re: Swingup external threading tool
Post by: John Stevenson on December 06, 2009, 05:16:36 AM
Or using a tapered tenon that will hold it secure by the turning forces and do away with any stop screws.

(http://www.stevenson-engineers.co.uk/files/swing%20holder.jpg)

Something along these lines will work for RH and LH threads and nothing protruding.

John S.
Title: Re: Swingup external threading tool
Post by: Rob.Wilson on December 06, 2009, 07:05:14 AM
Great Job Bogs    :thumbup:

Looks like another tool i will have to add to the things to make list

Regards Rob
Title: Re: Swingup external threading tool
Post by: bogstandard on December 06, 2009, 07:26:00 AM
Andy,

I had already looked at your solution, and unfortunately, rejected it. That was due to two things, the first could be fixed, and that is the bolt head protruding from the side, but the second bit couldn't, and that is putting a fairly substantial side loading onto the pivot, I wanted to do it so that the pivot is only used in a rotary motion with no or very little side loads onto it. Friction is going to be the killer on this job.

John,

The way you have shown is a fairly easy fix, and is much easier than the ways I have thought about up to now. Only one problem with it, with any side loads, I suspect it will try to make the two tapers ride up on each other, it might only be a tiny amount, but could a problem all the same. Plus although fairly easy for me to make, others might struggle with it, when they try to replicate the design (if it works of course).
 
But by using a straight sided plate in there, and a couple of brass faced screws, one from either side, I think it could definitely be a main contender for curing my problem, and I think it wouldn't cause too much trouble for people wanting to make one.

If you hadn't brought up your problem in the first place, it would have easily been done and dusted well before now :lol:

I would like to thank both of you for the trouble you have taken in making suggestions. As I have said before, I can't be expected to know solutions to everything, and I really appreciate a bit of input like this to get me moving again when I hit a problem.

I will see what can be done if I can get in the shop later.


John
Title: Re: Swingup external threading tool
Post by: Ned Ludd on December 06, 2009, 07:32:34 AM
Hi Mr. Standard,
Can you not have the toolpost at, say, 45 degrees and have a canted swing up part to hold the threading bit, in a similar way to some parting tool holders. That way you should be able to get it nearer the chuck and if combined with JohnS's taper seating, rigidity should not be a problem. Although for most purposes the design, as you have it, will be quite usable. Why not prove the concept before worrying about niceties, there is always room for the Mk2! or in my case Mk3 Mk4 Mk5 etc :D
May I again say I am a great fan of your work, writings and style. If only there were more people with a lifetimes worth of experience willing to share their knowledge with the "youth of today".
This really is the best forum for "light" engineering fans. :mmr:
Ned Ludd
Title: Re: Swingup external threading tool
Post by: bogstandard on December 06, 2009, 07:58:18 AM
Ned,

Many thanks again, I had already thought of the angled bit, but nowhere near as much as you are suggesting. I didn't want to complicate matters from the outset, because as you know, if it does eventually work, the simpler the method, the easier it is to reproduce for the masses.

A couple of my rules to making things, what isn't there, can't go wrong, and always try to make things as simple as possible, life is complicated enough as it is.

As was mentioned before, this isn't my idea, but a follow on from a suggestion, and I am sure, if I can get it to it's simplest state, and working correctly, I think we will both be very happy chappies.

I hope that my ramblings help a few people along the way.

We seem to be a bit of a dying breed, with all the latest technology coming along and taking most of the 'hands on' enjoyment out of it, so we need all the help we can get.

I would like to point out, even though this looks like a 'light engineering' site, it is a site for almost everyone to enjoy, and we have on here many artisans showing their work that isn't metal engineering orientated.


John
Title: Re: Swingup external threading tool
Post by: andyf on December 06, 2009, 08:25:06 AM
Bogs, I'm speaking as one of the newbie masses and this isn't meant as criticism, but might it be best first to continue along the original line with a relatively simple Mark 1 device for RH threading only, to see if that works before considering LH threads and the complexities they bring? My worries are:
(a) that if the first one you make is the complex version and it doesn't work, you will be discouraged from making the simple one where there is much less to go wrong, and
(b) that it's essentially a device which might appeal mainly to those as inexperienced as me. We might find it hard to reproduce the fine standards of fit around the tenon which the complex one needs if the toolholder is to flop nicely down but have minimal sideways play when in position.

Andy

Title: Re: Swingup external threading tool
Post by: bogstandard on December 06, 2009, 06:58:27 PM
Actually Andy, a little bit too late, I have already done it. It seems that your post didn't highlight when I checked the site just before I went into my shop late afternoon, so I just went ahead as I had planned.

But no problems, if it does work as planned, and it proves that it will work, then there is nothing wrong in making a very simple design from what you can gather from what I am doing. This isn't a slavish 'copy as I am doing post', but my ramblings captured in text and pictures as I progress along a development route, and if the concept doesn't work, then it will be recycled and forgotten about. But if it does, then it opens up a whole new idea to threading that could benefit a lot of people.

So at this time, I am running with a modified suggestion that John Stevenson came up with.

Because I am going down the route of a fully machined up tool holder, I have caused myself a problem for access to one area I need to cut a slot into. If you made a much simpler version than this, say with an 'L' shaped backplate, then you would be able to get a normal cutter in.

I had to use a woodruff cutter to solve my problem, so I made a few quick calculations.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup38.jpg)


Then set to work.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup39.jpg)


In no time, I had the two slots that I needed.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup40.jpg)


This is how the two slots lined up.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup41.jpg)


The uppy downy bit then got a dose of reshaping.
You will notice that I have gaps all over the place with this tool, and I have mentioned this before. This tooling will be working in a swarf producing environment, and unlike normal fixed tool holders, where it wouldn't cause a problem, because this tool is moving, swarf could get in and disrupt the nose setting of the tool and cause major cutting problems. These gaps are to try to give somewhere for the swarf to settle into without affecting the correct operation of the tool.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup42.jpg)


A quickie calculation gave me the size of block that will be required to give me the gaps I want.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup43.jpg)


I had certain scoffs when I first mentioned that I used a mini vice, but for jobs like this, they are indispensible. I was able to hold the small component very accurately while I swung the big cutter around, hacking the block down to size.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup44.jpg)


The block was machined to thickness so that it was a tight fit going into the swingy bit.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup45.jpg)


The block was then cut to the correct outside dimensions and I got out my secret weapon. A piece of what must be ten year old very worn out fine W&D paper. The block side face was then gently rubbed on it until it fit perfectly into the swing holder slot, with no side play but a nice smooth sliding fit. It took only a couple of minutes to achieve that state

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup46.jpg)


It was then loctited into the main holder.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup47.jpg)


So very close to being finished. A bit of lathework, a few holes to drill and tap and it will be ready for first trials.
Another point of interest is that the swing block protrudes slightly in front of the main block. This is another one of my attempts to keep swarf out of the operating bits.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup48.jpg)


I have been reliably informed by the better half that I need a haircut, I told her that I didn't, but you can guess who won. When I argued that things like that don't trouble her, 'cos she ain't got any at the moment, I was told it was either haircut or no shop time. So to get this finished off tomorrow, I am making a great sacrifice and dragging my weary bones to the chop shop. I just hope it is all worth it.


Bogs
Title: Re: Swingup external threading tool
Post by: andyf on December 06, 2009, 07:46:18 PM
I'm due for a shearing, too, Bogs. Seems to grow faster in winter - must be an evolutionary hangover from a furry Ice Age past. Mustn't complain; at least I get my money's worth at the barber's shop. And he's taken up my suggestion of substituting grey smocks for the dark blue ones against which the cuttings looked so depressingly grey  :(  Now, the silver hairs don't show up and I can take comfort from the remaining mouse-coloured trimmings  :ddb:

I suppose the simple answer to my misgivings over the tenon is to try it. If it stops the thing working smoothly, just loosen the Loctite with heat, yank it out and see if the device works without it for RH threads only.  I like the idea of the swarf gaps; apart from the swarf problem, they will reduce the contact area, and hence friction, between the parts when they move in relaion to each other.

Next instalment is eagerly awaited.

Andy

PS Might a hairpin-shaped light spring, located with a loop round the pivot, give more positive swing-down?
 
Title: Re: Swingup external threading tool
Post by: bogstandard on December 07, 2009, 12:24:37 AM
Andy,

That was the reason I left the top part on the main channel, if I couldn't get it to go down under gravity, I was going to drill a small hole in the swing block and pop a spring in there.

I seem to have answers for everything anyone comes up with, but what you don't realise, this had been fermenting in my head for over a week, and I had already looked at the thing from most angles. John's suggestion was the one that I hope will get this thing to a finished working tool, and that was the area I was stalling on.

Have a look at the C-o-C, that is now what I envisage a finished, easy to fabricate one would look like. A few easily made bolt together bits with a tiny bit of fine tuning on the block. Nowhere near as complicated as the one I have made. This would also allow for a complete swing away of the threading tool, for measuring the thread with a nut.

Mine had to be made as it was to cater for all known problems that I thought might crop up. It is always invariably the same, the prototype is always more complicated than the finished product.


John

I would just like to add, after all this work, it is still very similar to the original concept by Mike Cox, except for the block, moved pivot point and clearances for swarf.
Title: Re: Swingup external threading tool
Post by: John Stevenson on December 07, 2009, 04:09:06 AM
Devils advocate here  ::)

The swarf gap worries me, if there is a gap then small stuff will be OK as that what it;s designed for but what happens when it comes across thicker swarf?
Some may start to enter then wedge.

Most swarf will enter from the front, what about pushing an O ring over the end of the rocking holder to seal the gaps but still have them ?

John S.
Title: Re: Swingup external threading tool
Post by: jim on December 07, 2009, 04:32:04 AM
just a thought on the swarf, wouldn't it be possible to put a rubber "skirt" around the tool?

i look forward to seeing the end result :thumbup:
Title: Re: Swingup external threading tool
Post by: bogstandard on December 07, 2009, 04:38:17 AM
John,

I already have this in hand if needed. I was going to use a very thin bit of litho plate on the front and side of the tooling with just the threading tool poking it's nose thru. In fact on the trials to come, I was going to stick double sided tape to the outside of the temporary plate to see just where the swarf would be causing a problem, by seeing where it ended up when it stuck to the tape.

Talk about R&D, no flies on me on this one. It all might not be necessary, and the tool stays perfectly clean, but every angle has to be explored initially.


John
Title: Re: Swingup external threading tool
Post by: andyf on December 07, 2009, 08:11:36 AM
How about a thin metal shield, as C-o-C below, attached to the swinging part at points X, and covering the top and front of both the swinging and fixed parts? The top and front of the swingy bit would each need to stand slightly proud of the top and front of the fixed part, and swarf might still get in if the top of the shield had to be narrow so as not to foul the toolpost dovetail and any height adjuster on the fixed part.

Andy

(http://i689.photobucket.com/albums/vv257/andyf1108/Swing-upchipshield.jpg)
Title: Re: Swingup external threading tool
Post by: bogstandard on December 07, 2009, 11:07:30 AM
Andy,

That is the sort of idea I mentioned.

At the moment, I have to get back into the shop and finish it off, and a shield will only be considered now after I see what is going to happen during the try out.

I don't want things to get too clouded by 'maybe' problems.


John
Title: Re: Swingup external threading tool
Post by: bogstandard on December 07, 2009, 05:10:37 PM
I didn't manage to get into the shop until this evening, so I rushed thru everything, then took some piccy's of what I had made.

The first thing was to get the holes drilled and tapped. I located the swing arm onto the little block and clamped it down onto the block top face, then the pivot position was drilled and threaded. The other holes were just for tool clamping screws and the height adjustment for the main block.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup49.jpg)


A pair of phos bronze flanged bushes were made up and reamed 8mm. They had flange thicknesses that were in line with the gaps required and the position of the block. I also knocked up a stepped pivot bolt. I made the length so that when it was fully tightened down, the swing arm still had a few thou side to side play only at the pivot point, there was no rock at all at the cutter tip. If this play causes a problem, the bolt shoulders can easily be adjusted to snug things up a little.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup50.jpg)


A bit of threaded rod and a height adjusting knob were easily knocked up.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup51.jpg)


These are all the bits now assembled, and the tool completely finished. I had to fine tune the block a tiny bit as it was still a little tight, by removing a few tenths and a dab of oil on the block and pivot, the swing arm now easily rattles up and down, and no sign of side play at all. I'm very happy with the results and how well it went together.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup52.jpg)


This is now set up for correct height on my machine.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup53.jpg)


I just didn't have time tonight to get a trial done, and from very early tomorrow morning, I have personal things to do that will leave me incapacitated for a couple of days, so I am sorry, you will have to wait a little longer. I would like to do a vid of the results if they are satisfactory, unfortunately I don't have a camera mount for my machinery yet (another tuit), so you will have to take my word for it.


Bogs.
Title: Re: Swingup external threading tool
Post by: andyf on December 07, 2009, 05:23:29 PM
Looks terrific, Bogs  :thumbup:

It'll be interesting to see how well it works, once circumstances permit.

Andy
Title: Re: Swingup external threading tool
Post by: mklotz on December 07, 2009, 05:27:00 PM
I'm sorry, John, but I'm having an attack of the stupids here.

It looks to me like the tool can only swing up only a tiny amount - a degree or two.  Is that enough to clear a thread while you wind the carriage to the right?  Do you swing it up with your finger - there doesn't seem to be a handle in sight?

Do a befuddled colonial a favor and snap a few pics of it being retracted and/or provide a few words about how it's used in anger.

BTW, it looks stunning.  I wouldn't bother you with these questions but Santa is bringing me a QCTP and I'd love to make one of these assuming I can understand its operation.
Title: Re: Swingup external threading tool
Post by: bogstandard on December 07, 2009, 05:55:46 PM
Not 'stupids' at all Marv. It took a little bit to get my head around it.

The only problem is that it will only work on a machine where you can reverse the the whole machine including rotation of the chuck.

Just to explain basically how it SHOULD work.

There is no manual retracting of the cutter at all.

As you know, under certain conditions, you have to leave the leadscrew engaged when cutting threads, on my machine, whenever I cut Imperial threads. When you cannot use the drop in dial.

You take a threading cut as normal, when you reach the end where you usually retract the tool with the cross slide, you don't retract, you just put the machine into reverse, to take the tool back to the beginning. As the tool starts to go back along the thread just cut, because the chuck is running in reverse, the tip of the tool is lifted by the non cutting action. It should only be a few thou lift, that bit has to be tried out yet.

When it reaches the start point again, the tip should automatically drop to the cutting position, so another cut is put on with the compound and run in the normal way. It should work for cutting both right and left hand threads.

If it works, it saves having to retract the tool, and then reset it to zero each time. It does away completely with that part of the cutting regime.

Not a very good explanation Marv, but I hope it strikes a light.

All we need now is to see the work wasn't all in vain. If it doesn't work, shrug shoulders, at least we tried.


John
Title: Re: Swingup external threading tool
Post by: Darren on December 07, 2009, 05:59:37 PM
Like Marv I was wonderin'  :scratch:

But I gedit now  :clap: Ain't that clever thinking Mr B ...  :smart:


Fingers crossed it don't chatter during cutting, I surely hope not cos I'd like to copy that little marvel ....  :dremel:
Title: Re: Swingup external threading tool
Post by: mklotz on December 07, 2009, 06:07:38 PM
Thanks a heap, Bogs.

I've got it now.  My confusion arose because I was thinking of more traditional threading using the threading dial - put on a cut, disengage half nuts, lift tool to run carriage back without retracting cross slide, put in more cut on compound, drop tool, wait for threading dial, reengage half nuts and make another cut.

Now that I see you're moving the carriage to the right under power to avoid losing sync, it's all pretty obvious.

Very ingenious.  I hope it all works under fire.
Title: Re: Swingup external threading tool
Post by: NickG on December 07, 2009, 06:49:15 PM
Looks great John and should work fine - I get it too now!  :lol:

Nick
Title: Re: Swingup external threading tool
Post by: Divided he ad on December 07, 2009, 07:38:13 PM
I've just read through all this.... Still playing catch up  ::)



Nice looking tooling there John..... You said it was high on the list...... All confidence in the testing when you get to it  :thumbup:





Ralph.
Title: Re: Swingup external threading tool
Post by: sbwhart on December 08, 2009, 02:22:13 AM
Penny dropped now John  :thumbup:

Great work

Stew
Title: Re: Swingup external threading tool
Post by: Stilldrillin on December 08, 2009, 04:39:54 AM
"I can see clearly now the rain has gone".......  ::)

Gotcher..... Now!  :thumbup:

Great work John.

David D
Title: Re: Swingup external threading tool
Post by: Bernd on December 08, 2009, 09:27:53 AM
Like Marv, I had the same question as to how exactly it was supposed to function.

What hasn't been mentioned is the backlash or gear wind up in the gearing system of the lathe. When reversing the lathe wouldn't there be a delay from the time that chuck starts to spin backwards to the time the lead screw starts moving the carriage backwards? Seems to me the tool would be cutting the backside of the thread you just cut or even maybe cut the thread in half depending on the gear train backlash.

To me it would see that if there was "0" backlash through the whole gear train a swingup threading tool wouldn't be needed.

Perhaps Marv is right in his assumption that the tool should be lifed clear of the work altogether!

Bernd
Title: Re: Swingup external threading tool
Post by: Darren on December 08, 2009, 09:41:15 AM
Bernd, I believe because the tool can lift then there will be no pressure to do any cutting (even with the back edge) The tool should simply ride the waves.
Title: Re: Swingup external threading tool
Post by: NickG on December 08, 2009, 09:51:03 AM
Bernd,

Good point about the backlash, I've wondered that too but I think as Darren says it will just ride up the thread a little and it's going in reverse so there isn't a cutting edge on the work. Might put minor marks on it but doubt it the pressure will be so light it would just be like a nut going up the thread.

Nick
Title: Re: Swingup external threading tool
Post by: bogstandard on December 08, 2009, 10:08:21 AM
If you had read and inwardly digested my basic description on how it should work, you should have realised that the chuck is running in reverse.

So how could it cut with the metal being turned away from the cutting edge?

Rather than destoying the concept and jumping to conclusions before proven, wait for the results.

Only then should suggestions and criticisms be brought forwards.


Bogs
Title: Re: Swingup external threading tool
Post by: andyf on December 08, 2009, 10:11:08 AM
To my mind, the best way to think of it is that it works like a simple hinged clapper box on a shaper. It lets the tool skid over the surface when the spindle is reversed to run the carriage back, just as the shaper tool does on the return stroke. At least, that's what it's supposed to do - I'll be sorry I ever mentioned the idea if Bogs finds it doesn't work now he has put so much additional thought and effort into it.

Andy
Title: Re: Swingup external threading tool
Post by: Darren on December 08, 2009, 10:14:49 AM
John,

Bernd did say in his post that the chuck would be turning backwards  :thumbup:

On my mini lathe there was no backlash worth mentioning, so reversing the machine without retracting the tool was fine.

On my old Union lathe there was plenty of backlash, if the tool wasn't retracted it would cut the thread off quite merrily even though only the back of the tool was in contact with the work.

I think this is was Bernd was referring to?

Title: Re: Swingup external threading tool
Post by: Darren on December 08, 2009, 10:15:46 AM
To my mind, the best way to think of it is that it works like a simple hinged clapper box on a shaper. It lets the tool skid over the surface when the spindle is reversed to run the carriage back, just as the shaper tool does on the return stroke.

Andy

Nice comparison Andy  :thumbup:
Title: Re: Swingup external threading tool
Post by: 75Plus on December 08, 2009, 10:19:36 AM
I'll be sorry I ever mentioned the idea if Bogs finds it doesn't work now he has put so much additional thought and effort into it.

Andy

My guess is that Bogs is NOT reinventing the wheel he is just finessing it a bit. :D :D

Joe
Title: Re: Swingup external threading tool
Post by: Ned Ludd on December 08, 2009, 11:39:36 AM
Hi Guys,
Can't help but think that the tool will have to rise clear of the work, even if it doesn't cut there will surely be a side ways force trying to bend the pivot. Didn't want to be the first to bring this up, the last time I commented, about the retracting tool holder, Mr Standard stopped work on it. :(
Ned Ludd
PS now found camera and charger, so will soon post piccies, I hope.
Title: Re: Swingup external threading tool
Post by: NickG on December 08, 2009, 11:47:42 AM
There won't be any sideways force, as the vertical component of the force (due to angle of thread and relief angle on tool) will push the tool upwards as there is nothing holding it down. So the tool should ride up a bit further on the thread flank.

Lets wait and see.

Nick
Title: Re: Swingup external threading tool
Post by: jim on December 08, 2009, 12:04:14 PM
i'm really looking forward to a vid of this in action.

looking real good :clap:
Title: Re: Swingup external threading tool
Post by: khand on December 08, 2009, 12:15:16 PM
I made a holder for some carbide threading inserts about a month ago and was planning on making it retractable but I like your idea a lot better. Can't wait to see how this turns out.
Title: Re: Swingup external threading tool
Post by: Bernd on December 08, 2009, 01:43:09 PM
Bogs,

I'm not trying to destroy the concept. I'm wondering out loud about the backlash you have in the gearing between the chuck and the carriage moving so the tool will stay in the cut slot of the thread. It's the same principle as withdrawing the cross slide and having to go past your setting and then back in to take up the backlash. That's what I was thinking about.

Bernd

Note Added: Just did a test on my Logan lathe. Set up for 20 threads. Ran machine in forward, as if cutting threads. Then reversed the motor. It took a 1/4 of a turn on the chuck before the lead screw started to turn and one full turn of the chuck before the carriage started to move.

I must have one sloppy lathe when it comes to back lash then.
Title: Re: Swingup external threading tool
Post by: AdeV on December 08, 2009, 03:21:00 PM
[deleted due to off-topicness]
Title: Re: Swingup external threading tool
Post by: bogstandard on December 10, 2009, 12:55:28 PM
I have now unlocked this topic again, to show you what has happened on the testing.

I could only manage an hour this afternoon so not much to show, but a lot to talk about.

I had set everything up as I would normally set up for threading, using the normal offset method. I set the lathe to cut a 2mm pitch.
A lump of 1" nylon bar was used for the first cuts, if something was going to go drastically wrong, I didn't want my tipped cutting tool damaged.
Everything worked exactly as planned, it cut the thread perfectly and when the lathe was flipped into reverse, the tooltip lifted, wound back to off the job and duly dropped down into the cutting position again. I carried on for a few more cuts, and nothing changed, it behaved perfectly.
This now gave me a little more confidence in what I was doing, so then I thought that it was time to give it a good try out.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup54.jpg)


Raiding my steel recycle box, I came up with some of the worst crap to thread, a length of 7/8" diameter steel conduit. This stuff is made from the dregs of the steel world. I was expecting major problems.

So after mounting it up, it was threaded the same way as I had done the nylon, with exactly the same results, except that the finished threads were real rough, but I had expected that because of the material, it is no better when you thread it up with a die when fitting it up in a factory.
There was no chatter, jumping or farting, in fact nothing out of the ordinary, except it only took me a fraction of the time it would normally take.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup55.jpg)


So after a quickie switchover, I swapped it to 5mm pitch, and carried out the same exercise on the other end of the pipe. I couldn't go any deeper otherwise I would have been thru the tube wall.

Results.

This is getting monotonous, exactly the same as before.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup56.jpg)

Conclusions after this very short trial.

This really wasn't a full trial, but an initial proving run. Until smaller threads are cut then a final conclusion cannot be forecast, but if it goes like these three have gone, it should mean that this concept is definitely a winner, and could be designed to be made much simpler.

I found that when using it, I sat on my stool, with one foot on the brake and one hand on the fwds/rev lever. It was so simple to do, put on cut using topslide, start the machine fwds, stop when at end of cut, flip machine into reverse, run off the end of job then stop, repeat process. In fact it is easier than trying to use the drop in dial, no waiting about or counting. So for me, I will use this method all the time, rather than mucking about with other settings.

I have now to make a camera mount to video the process and to prove the concept on other materials and sizes.

BTW, after seeing how the swarf behaved, I don't think that will be a problem at all.

Now gents, is the time for your criticism, worries and conclusion jumping.


Bogs


Title: Re: Swingup external threading tool
Post by: Bernd on December 10, 2009, 01:14:58 PM
Bog's

Well, I was proved wrong in thinking that the backlash of the machine would mess up the threads. I was thinking that with the backlash of my machine that it would take the tops off of the thread going in reverse. I came away with that conclusion because I used the regular way of mounting a cutting tool, or solid mount and ran the machine backwards after having it set up to 8 threads per inch. When reversing it the carriage didn't start moving until I was half way between the threads. Thus the conclusion that the tool needed to be rasied all the way above the part manually.

I now stand corrected on that matter of thinking. Perhaps you have some insight as to why I would have thought this? (yes I know what you'd like to call me, but be kind please)

And thanks for finishing the thread. I really didn't want to build a tool and prove that my thinking was in error.  :nrocks:

Regards,
Bernd
Title: Re: Swingup external threading tool
Post by: Rob.Wilson on December 10, 2009, 01:27:52 PM
 Nice one Bog's    :headbang: :headbang: :headbang: :headbang:


Regards Rob
Title: Re: Swingup external threading tool
Post by: Divided he ad on December 10, 2009, 02:06:26 PM
Job done!


Awaiting full trial testing..... When ever, I've never even tried threading! This is pure curiosity for me  :)





Ralph.
Title: Re: Swingup external threading tool
Post by: bogstandard on December 10, 2009, 03:59:40 PM
Bernd,

I wasn't really angry, and the reason I locked the post was to prevent any more people jumping to unfounded conclusions, before we had a look at what the tool actually does, rather than assuming what it would do.

I think a few people could have got themselves into an apology situation, including myself, when of course that isn't what posting on here is all about.

With regards to your backlash worry. I actually set my machine gearset up a little loose to give me that condition from the start, not a lot, but enough, and I have to tell you that I found nothing to worry about on that score. But I did retract a little more than I would normally do (about 1" past the end) just to make sure it was in synch again before it took the next cut.

I am going to try cutting down to 1/8" diameter bar, just to see if the weight of the supported tool causes any problems with bending of the said piece of metal. If it can do that small, then I think that will satisfy most needs. Also to be done is left hand threading, but I expect no problems at all with that. I would really like to do a very large thread as well, but I will have to see what spare metal I have that I can afford to waste on these trials.


I am so happy with how it went this afternoon, I've still got a silly grin from ear to ear. Just hope it doesn't get knocked off by the next bit.


Bogs

I had forgotten to thanks Rob and Ralph for the comments, but also to say to Ralph, if this does turn out as planned, it could make threading for people like yourself much easier, as long as you have a lathe that reverses.
Title: Re: Swingup external threading tool
Post by: ariz on December 10, 2009, 04:28:11 PM
I'm happy to see that everything went well with the test, because this sort of threading (making a thread) is the only one that I use: fwd, stop, retract, bckwd, stop, etc. without disengaging the gear
so, this very useful tool will be on top of my to-do list
thank you bogs (and everyone who contributed)  :nrocks:



Title: Re: Swingup external threading tool
Post by: Bernd on December 10, 2009, 06:20:14 PM
Bog's

I'm glad the tool is working out.

I did learn one valueable lesson from this though, and that is shut up untill the test results are in.  :)

Bernd
Title: Re: Swingup external threading tool
Post by: John Stevenson on December 10, 2009, 07:13:59 PM
What about stopping a tipped tool in the cut without the help of a run off groove ? That part sounds like the recipe for a chipped tool.

John S.
Title: Re: Swingup external threading tool
Post by: Ned Ludd on December 10, 2009, 07:47:01 PM
Hi Mr. Standard,
I can't tell you delighted I am that the tool worked well.  :clap:
I am always pleased to be proved wrong, as long as the net result is greater overall knowledge.
Glad to have you back.
Ned Ludd
Title: Re: Swingup external threading tool
Post by: bogstandard on December 10, 2009, 11:00:56 PM
Quote
What about stopping a tipped tool in the cut without the help of a run off groove ? That part sounds like the recipe for a chipped tool.

I just knew John  would pick up on something I had done. But I did have an excuse, I rushed all these threads thru with the bare minimum of preparation, otherwise you wouldn't have got any results at all.

I have Stew calling round later today, so I suppose I will have to prepare a part for giving him a demo, and I promise to have the correct depth runout slot.


John
Title: Re: Swingup external threading tool
Post by: andyf on December 11, 2009, 06:23:18 AM
It's starting to look pretty effective, Bogs - great! As to 1/8" stock, I doubt that the weight of the tool and its holder would cause any problems when reversing. To my mind, the force exerted on the stock involved must be much less than when actually cutting a thread into the same size stock. But I suppose that a practical test will reveal whether it works as well on slender stuff, and in cutting small pitches.

Quote
I have now to make a camera mount to video the process
Quote
I have Stew calling round later today, so I suppose I will have to prepare a part for giving him a demo
Maybe Stew could be prevailed upon to act as a camera tripod bipod   :)

Andy
Title: Re: Swingup external threading tool
Post by: bogstandard on December 11, 2009, 10:56:28 AM
Andy,

We tried that, but Stew seemed to be a bit of a jinx and we could only get a 14 second clip each time we tried.

So one piccy and a 14 second clip is all you are getting this time.

I managed to find a lump of 2.5" brass that I could cut a thread on. So away I went and cut a 5mm pitch on it, which is near enough to a 5 tpi thread for comparison. The holder I have made caused a problem in that the top overhang wouldn't allow the tool to come up high enough for really large threads, but that is a problem that can easily be overcome. But with a little coaxing we got it done. Other than that, the cutting action couldn't be faulted, it just went ahead and did it, just as planned.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup57.jpg)

And for all you video nuts, this is as much as it would record each time, so this will have to do you until I can work out what is wrong with the camera settings. But at least it shows the full cutting and retraction action, just.



Stew can be my independant witness that the tool really does work (otherwise he doesn't get the free beer at Christmas).


Bogs
Title: Re: Swingup external threading tool
Post by: NickG on December 11, 2009, 11:02:00 AM
Nice video Bogs, it did exactly what I thought  :clap:  :beer:
Title: Re: Swingup external threading tool
Post by: sbwhart on December 11, 2009, 11:08:11 AM
Stew the bipod reporting in.

All worked perfectly, that course thread was a real tester with a little bit of tunning John had it working real nice.

The worst problem was from my driving ability of the camera "but i only pressed the button once John"  "it should record more than that lets have another go" "honestly John I only pessed it once" "somthings wrong lets have another go" :-------------------------

And then John spilt blood when he slipped and craked his shin on his machine stand

  OUCH

 :( :( :(

I learnt a few new RAF words

 :D :D :D

Stew

Title: Re: Swingup external threading tool
Post by: Rob.Wilson on December 11, 2009, 11:54:50 AM
Great job Bog's 

The tool works a treat  :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap:

Regards Rob
Title: Re: Swingup external threading tool
Post by: khand on December 11, 2009, 01:06:35 PM
I knew it was going to work. Nice job. :clap: :clap: :clap: :clap: :clap:
Title: Re: Swingup external threading tool
Post by: Bernd on December 11, 2009, 02:42:44 PM
Very nice indeed. I like the way that tool pops up when it reverses. Sure looks like it'll make thread cutting faster and easier.  :thumbup:  :clap:  :clap:  :clap:  :clap:

Can't believe how fast your lathe stops. Is there a brake on it? Also there seems to be no backlash from the time the chuck reverses and the carriage starts to move backwards.

This going to get me to look at why I've got so much slop in the drive train. :scratch:

Stew, you do make a nice bipod.  :lol:

Bernd

Title: Re: Swingup external threading tool
Post by: jim on December 11, 2009, 02:48:26 PM
 :clap: :clap: :clap:

very impressive,  :thumbup: :thumbup:
Title: Re: Swingup external threading tool
Post by: gingerneer on December 11, 2009, 04:23:03 PM
Thats neat, yet another project added to the list.
Title: Re: Swingup external threading tool
Post by: andyf on December 11, 2009, 04:35:47 PM
The vid was commendably brief, showing all it needed to in those 14 seconds  :thumbup:. I'm really glad the tool seems to be proving itself useful, Bogs. Though it wasn't my idea, I passed it along to the group and was worried about having to slink off into the undergrowth if the concept turned out to have any major drawbacks.

Having successfully inveigled you into all the R&D and actually making one, I'll just have to make one for myself.
Hope the damaged shin isn't too painful.

Andy
Title: Re: Swingup external threading tool
Post by: Darren on December 11, 2009, 05:15:02 PM
I've been eyeing up a lump of steel tonight sitting idley  in the corner probably trying it's best to hide from me ....

So much to do .....
Title: Re: Swingup external threading tool
Post by: bogstandard on December 11, 2009, 05:46:00 PM
Gentlemen,

Many thanks for the compliments, but things are not quite wrapped up yet. A couple more tests to do. I hope they go as well as this one did.

BTW, I found the problem with the camera, I had formatted the card a while back but I have never had to do a vid since, so the problem didn't show. I had formatted it to Fat system rather than Fat32.

Bernd,

I have a shoe brake system on my machine, complete with a drum, just like a car, it is very efficient. I thought this was a lot of backlash on my machine since I had set it up, so just how bad is yours?

Andy,

I would just like to thank Mike Cox again for the inspiration to get me to do a bit of R&D on his concept. This has definitely been one of the easiest projects I have ever worked on to get good results so fast. Usually it takes a lot more thinking power. But of course, the clincher was when John came up with the block idea, it got me past the mental blockage that I had. So the glory is nowhere near all my own, but other peoples' inputs and ideas as well.

If it does go on to really prove itself, I honestly think it will transform the way I personally do threading. But that isn't the main reason. Looking at it, and the quickie sketch I did earlier about a much easier design, it could make single point threading much easier for the people who have been scared to try it out before now. This method certainly makes threading at least 50% easier and quicker. It is a shame it can only be used on a lathe with full reverse on it.

In fact, I think a piece of 2" side by 1/4" or 3/8" thick angle iron would be perfect for the main frame, so don't go looking at big lumps of metal just yet Darren.

Bogs
Title: Re: Swingup external threading tool
Post by: Divided he ad on December 11, 2009, 06:50:56 PM
Nice  :thumbup:


Does as it should as far as I can see.... Nice camera work Stew  :clap:



I'll have to look into this threading lark one day...... Suppose I'd best use my 'shop to get that even close to sorted!?




Nice Job John, and then ideas men too :thumbup:





Ralph.
Title: Re: Swingup external threading tool
Post by: bogstandard on December 12, 2009, 08:23:52 AM
So now we come to the final part of this R&D exercise. I made up a very complicated camera mount for my machine, it took me ages, about 15 mins of real hard work.


Grabbed a bit of ali from the recycle box (this was a piece from my original slide for the tailstock mounted DRO head).
Two holes drilled, the end one tapped.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup58.jpg)


Screwed onto the mag base.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup59.jpg)


Then the camera was screwed onto the assembly.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup60.jpg)


By doing that, it allowed me to make this vid, all by myself.
I was talking to Stew yesterday about working while other people are in your personal shop space, and nothing ever seems to go right.
This time, no problems, except you will see at the very end of the vid, I ran out of memory on the camera card.
Before anyone comments, I should have swung the topslide the other way for left hand threading, but for this proving job, I left it as it was, set for right hand threading.




Just to prove I was cutting a 40 tpi thread on that bit of 3/32" (about 2.5mm) brass bar, here is a close up.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup61.jpg)


Well that seems to be the end of this little exercise. The tool cuts both left and right hand, and John's worry about getting close to the chuck is now no longer a worry.

I honestly don't think that swarf will be an issue. Just keep an eye on it, and if any does get in there, it is dead easy to blow or brush it out.

I was going to make another toolholder, based on the design on my sketch, but because I want to get onto other things, I don't think I ever will. This one will do me just fine for 99% of all the external threading I will be doing, and if I come across something it won't do, then I will just do it the old fashioned way.

I hope you have enjoyed this journey on how I get around to and do things. With plenty of forwards thinking and problem solving, and a little help from friends, you can achieve almost anything.

I do hope that a few of you will be spurred on to make the easier version of this tool, I am sure you won't regret it.



Bogs
Title: Re: Swingup external threading tool
Post by: andyf on December 12, 2009, 08:58:56 AM
Wow, it really is good, isn't it?

Just as a closing note, thanks to Bogs for taking us through everything, and many thanks to Mike Cox. As already mentioned, he floated the idea and showed his prototype on another machining group. I'll invite him to take a look at this thread.

Andy 
Title: Re: Swingup external threading tool
Post by: chuck foster on December 12, 2009, 10:19:49 AM
nice video and better yet, nice threading  :thumbup: :clap:
that tool holder is very simple and it looks like it works very well.............now i will add that to my list of things to make.

thanks for taking us along for the ride john.

chuck  :wave:
Title: Re: Swingup external threading tool
Post by: Bernd on December 12, 2009, 06:44:49 PM
Bernd,

I have a shoe brake system on my machine, complete with a drum, just like a car, it is very efficient. I thought this was a lot of backlash on my machine since I had set it up, so just how bad is yours?

Bogs

John,

The old Logan I've got doesn't have a brake on it so I'd need to run it real slow for one thing.

Second, when I reverse the machine the chuck will start to turn and at about a 1/4 of a turn of the chuck the lead screw will finally start to turn. Then after the chuck has made almost a full revolution backwards the carriage will finally start to move. Have I made this clear enough to understand? That is one reason I think this tooling will not work in "my" machine.

I'm sure that the gears on the headstock probably have more backlash than they need. As far a the lead screw is concerned, I'll have to take a closer look.

In the mean time I guess I'll just have to resort to turning the cross slide out of the way.

BTW, I'm amazed at how nice that tool follows the thread groove backwards. Great job.

Bernd
Title: Re: Swingup external threading tool
Post by: websterz on December 12, 2009, 08:58:15 PM
 :bow: John, that works a bloody treat!  (Did I say that right?  :lol:) The camera mount is icing on the cake...I gotta' build one of those! 

:proj:
Title: Re: Swingup external threading tool
Post by: bogstandard on December 13, 2009, 10:58:36 AM
Thanks gents, and spot on Webs.

Just to prove I am not all hot air, and that I do use the bits I make, I had a chance to try this out today.

Here is the job ready prepared for threading

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup62.jpg)


Thread cut

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup63.jpg)


Chuck tried and fitted perfectly

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup64.jpg)


The last bit for my interchangeable tooling, a 5c to Myford adapter to fit the spindexer.

(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup65.jpg)


I can honestly say that it was the easiest bit of single point threading I have ever done.


Bogs
Title: Re: Swingup external threading tool
Post by: andyf on December 13, 2009, 12:13:24 PM
Quote
Berndt: when I reverse the machine the chuck will start to turn and at about a 1/4 of a turn of the chuck the lead screw will finally start to turn. Then after the chuck has made almost a full revolution backwards the carriage will finally start to move. Have I made this clear enough to understand? That is one reason I think this tooling will not work in "my" machine.

To my way of thinking, Berndt, it won't matter if the chuck starts turning (in reverse) before the carriage starts moving. The flank of the part-cut thread will rub on the side of the tool, and move it up out of the way. I can see that if your chuck turned more than 1800 before the carriage moved, and you were cutting a small pitch thread, the tool might rise up the flank of the thread and then drop back down the other side of it, but all that would happen is that the thread flank would push the tool up again once the chuck had gone round 3600, with no detriment to the tip of the tool.

A simple test could be arranged :smart:: Instead of a tool, grip a bit of thin slightly springy metal with a 600 point on the end in the toolpost at centre height, with lots of overhang so it can spring up and down. Engage its point in the thread of a bolt held in the chuck. Then, with the change gears set up for the same thread as the bolt, try running the carriage to and fro. My bet is that the tip of the "tool" will rise and fall as required. If the tip gets mangled, I'm wrong  :bang:.

Andy
Title: Re: Swingup external threading tool
Post by: Bernd on December 13, 2009, 02:09:14 PM
Andy,

That sounds like a good test. Will have to try that. Won't be right now though. Thanks.

Bernd
Title: Re: Swingup external threading tool
Post by: bogstandard on December 13, 2009, 02:27:51 PM
Bernd,

When Stew called around the other day, and we cut that very large thread, we encountered a major problem when the tool was deep in, about 4mm (0.160"). On retracting out of the runout, the side of the cutting tool jammed on the side of the thread. It was caused by the swing part of the tool not being able to rise enough to clear. All I did was a quickie hack out of the main tool holder on the top overhang. Once that was done, and the tool could lift as far as it wanted, it just climbed as high as it needed to go, and dropped back into the cutting position when it reached the end, as shown in the short vid.
So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.


John
Title: Re: Swingup external threading tool
Post by: Ned Ludd on December 13, 2009, 03:37:37 PM
Hi Mr Standard,
I think that is what your "detractors" were worried about, the not being able to rise up enough. Sounds like your fix (could you call it the Viagra modification, getting more of a rise. :lol: sorry 'bout the bad joke could not resist) has done the trick.
 
Ned Ludd
Title: Re: Swingup external threading tool
Post by: andyf on December 13, 2009, 04:18:19 PM
Quote
Bogs: So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.

Not sure that gear sync would be an issue, Bogs, because the drive from spindle to saddle will be engaged throughout. Won't the tool just need a moment to drop down again before starting the next cut? Unless you are working at lightning speed, that will happen while you are stopping, changing the spindle from reverse to forward, and starting off again.

Incidentally, Mike Cox has viewed this thread and says "I am amazed that my simple idea could generate so much
interest and discussion. I only wish I had the skill and equipment that Bogs has. It is very satisfying that in the hands of a skilled worker the idea was taken to perfection."

Andy



Title: Re: Swingup external threading tool
Post by: bogstandard on December 13, 2009, 04:50:14 PM
Ned,

When I did the sketch earlier on in this post, it shows the backing plate as an 'L' shape, rather than mine which is a 'C' shape. I did that purely to make it easier for producing one of these tools, and even though I didn't think of it at the time, it automatically solves the problem of allowing the swing to get up high enough. I did mention though that it would allow the swing to be lifted completely out of the way for checking the fit of the thread with a nut. A thing I can't do with mine, I have to retract even further back to be able to get in.

I think that is called a lucky bit of design work, or getting it right without thinking about it.

Sorry Andy, that should really be phrased as 'to take up the backlash' rather than 'back into synch'. But you know what I mean. It will require retracting further as all the gears and shafts will have to take up all the gaps to go in the opposite direction, and won't all be in the correct position until it has travelled a certain distance, some parts will move by friction alone and won't be in the correct place until there are some 'pressures' working in the train.

I'm glad Mike was pleased with the results. It isn't just being discussed on here, but other places as well, and it seems to have had a very positive reaction.
 
Someone has even commented that he might have seen the idea before in a book. But I'm not worried about that, in a book is no use unless all the people who can benefit from this design can see it. We have just brought it out into the open if that is the case, where maybe thousands who haven't got the book can benefit from it.

All I can say is, I am one who has definitely benefitted, 'cos I got one.
You lot will have to make your own. :lol:

If he wants any more ideas as good as this one developing, just tell him to throw it open on here, I am sure someone will run with it.


John
Title: Re: Swingup external threading tool
Post by: Bernd on December 13, 2009, 06:34:29 PM
Bernd,

When Stew called around the other day, and we cut that very large thread, we encountered a major problem when the tool was deep in, about 4mm (0.160"). On retracting out of the runout, the side of the cutting tool jammed on the side of the thread. It was caused by the swing part of the tool not being able to rise enough to clear. All I did was a quickie hack out of the main tool holder on the top overhang. Once that was done, and the tool could lift as far as it wanted, it just climbed as high as it needed to go, and dropped back into the cutting position when it reached the end, as shown in the short vid.
So even if it was riding on the very top of the tips of the threads already cut, once it had dropped off the end, and if you left enough runup to the job to get all gears back into synch, I don't think you would have any problems at all.


John

This is what I was trying to get across, but didn't quite get it right in writing. I figured with a deeper thread it would do what you mentioned. But as you say if you give the tool more room to tip up it'll work.

I'm glad it all worked out in the end.

Looks like I'll probably make one of these some time down the road. Thanks again for your presistence on this project.

Bernd
Title: Re: Swingup external threading tool
Post by: bogstandard on December 14, 2009, 06:33:17 AM
As a final act, I have done another rough sketch on how to put one of these together.

There are no dimensions shown as you can make it as large or as small as you want it to be. I am sure the members on here can cope with something like that. The things not shown are the pivot point bits. If you drill a plain hole to use, then a washer will be required between the swing up and the main body. If you fit bushes, as I have done, then the top hat flange will give the stand off required. You should make the step bolt to give a couple of thou side to side clearance. I would suggest giving the locating block a small chamfer on each of the top edges, to assist the tool in relocating itself if it has been completely lifted off the block as it was being retracted to the start.


(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup66.jpg)


Get in there and enjoy your screwing.


Bogs
Title: Re: Swingup external threading tool
Post by: davidfe on December 17, 2009, 04:44:44 PM
As a final act, I have done another rough sketch on how to put one of these together.

There are no dimensions shown as you can make it as large or as small as you want it to be. I am sure the members on here can cope with something like that. The things not shown are the pivot point bits. If you drill a plain hole to use, then a washer will be required between the swing up and the main body. If you fit bushes, as I have done, then the top hat flange will give the stand off required. You should make the step bolt to give a couple of thou side to side clearance. I would suggest giving the locating block a small chamfer on each of the top edges, to assist the tool in relocating itself if it has been completely lifted off the block as it was being retracted to the start.


(http://i202.photobucket.com/albums/aa102/bogstandard_photos/Swingup66.jpg)


Get in there and enjoy your screwing.


Bogs

Sir Bogs,

I noticed the photo is missing.

Great thread on threading.   :thumbup:

Regards
Title: Re: Swingup external threading tool
Post by: Divided he ad on January 02, 2010, 07:39:58 AM
Don't mind me.....

Just doing a favour for a friend    :beer:



(http://i289.photobucket.com/albums/ll221/dividedhead/Crap-o-Cad/Swingup66.jpg)


Job done  :thumbup:




Ralph.
Title: Re: Swingup external threading tool
Post by: Lykle on February 25, 2010, 04:51:40 AM
I really love these kind of threads (pun intended)

Anyway, all we need to do now is design the same kind of tool for internal threading.
That's the one that always get's me into trouble.

It could be a rotating shaft with stops and maybe a light spring load to keep it down. Or a weighted stop?
I think it would require quite some modification on the relief side of the toolbit, to make sure it does not grab the material while retreating.

Hmm, nice little design project.

Lykle
Title: Re: Swingup external threading tool
Post by: andyf on February 25, 2010, 06:42:46 AM
Hi Lykle,

It would be hard to make a swinging toolholder for internal threads. If it swings up, the tool will dig deeper into the side of the bore, unless the axis around which it swings is very close to the tip of the tool, so the radius of the arc described by the tip is rather less than the radius of the bore. I suppose it might be less difficult for threading holes of large diameter, but it would probably be easier to make a retracting toolholder like the one shown here http://www.gadgetbuilder.com/ToolHolders.html#Retracting , where the operator uses the ball handle at the end of each cut to slide the tool out of the thread so that the carriage can be wound back for the next cut.

Andy
Title: Re: Swingup external threading tool
Post by: Ned Ludd on February 25, 2010, 01:32:58 PM
Hi Guys,
Anybody thinking of building one of those retracting tool holders, should think again. Although it is an interesting project and is indeed nicely designed, it can be replaced by a simple cross slide stop for MUCH less work. The idea of a retracting holder for internal threads has merit but of a completely different design. Something like a round  boring/threading bar in an offset round sleeve, for fore and aft movement, but it would need some arrangement at one end to stop the bar rotating under load. I can see it in my mind but no time to make it real, where is Bogs when we need him?
Ned Ludd
Title: Re: Swingup external threading tool
Post by: Darren on February 25, 2010, 01:54:20 PM
After building and using a swingup threading tool for external threads I wouldn't want to use anything else.

For the little internal work that I may or may never do I'll just do it the old fashion way or use slide stops. I'll work that one out when I get there.
Title: Re: Swingup external threading tool
Post by: ieezitin on February 25, 2010, 05:36:27 PM
On the internal threading tool I donít think it would be that hard to make here is a quick sketch on the mechanism that sprung to mind.

My theory is you only need to retract .050 - .070 max Linear to clear the cutter for extraction. The actuator could be at the end of the boring bar and a knurled wheel for rotation to seat and disengage.

The beauty is when you hit 0 and 90 of the cam you have great forces working for you so movement or backlash should be minimal if  not zero.

All could be made on a lathe within a day maybe, the hardest thing would be the engineering of the cam and dimensioning after that its cake.


Any ideas please feel free to critique .

All the best.              Anthony.
Title: Re: Swingup external threading tool
Post by: andyf on February 25, 2010, 07:49:54 PM
Hi Anthony,

Hmm... I think it might have to be a bit more complicated, and rather more like Cleeve's version, to make it rigid enough to work with a boring bar-like tool for internal threading, which would (on your sketch) have to stick out to the left, rather than point straight up.

Andy

(in :coffee: and wet blanket mode)
Title: Re: Swingup external threading tool
Post by: bramley51 on March 28, 2010, 10:30:34 PM
Andy and John,I've just finished my self retracting tool,and I'm chuffed to bits.It works like a charm,even for an ijit like me. :).Thanks for presenting the design,single point threading no longer scares the cr*p out of me.
I can highly recommend this tool to anyone to anyone who's never tried single point threading 'cause it's "too difficult".
Make this tool,and people will pay good money to see you at work :D
Thanks again,guys. :nrocks:
Title: Re: Swingup external threading tool, INCLUDES WARNING !!!!!!!!!!!!!!!
Post by: troup on May 15, 2010, 06:31:51 PM
Must be something in the water here in NZ, over half the people I know of from the interwobble who've run with this idea have been kiwis.

To whom I have now added myself, and will post more details, but I have a WARNING for those with a VFD who feel inclined to take the idea to the logical conclusion, and add some sort of automatic reverse.

What I'm talking about is a sort of self-acting "canned cycle", so you can thread pretty much like an NC lathe for the price of a switch or two.

Going directly from "full steam ahead" to "full astern both" used to be the preserve of turret lathes (eg Herberts with massive 4 speed motors and 'plug reversing') or the likes of John Stevenson's Tos, but now with VFDs it's as simple as adding a single changeover limit switch (a normally open pair AND a normally closed pair of contacts) or two simple limit switches. If either the switches or the dogs can be relocated, your lathe can automatically and accurately cycle through the threading zone ad infinitum, leaving you to simply increment the cut. (Runout grooves can be narrower, threading speeds higher > better finish, quicker job completion: all very enticing....)

HOWEVER this silver lining does have at least one cloud:

particularly when commissioning the reversing facility for such a setup, be aware that repeated reversals can cause a scroll chuck to self-open, to the point the jaws fly out. I learned this last night by almost having it happen. Yikes!

The scroll is the flat disc with a single spiral groove which engages with the teeth on the backs of the jaws, and also with the bevel gear pinions with the square recesses for the key.
The mechanism of the self actuation is that the scroll (at least on a bigger chuck) has a lot of rotational inertia if you're doing say 250 rpm in one direction. It wants to continue doing so even when the lathe suddenly switches to 250rpm in the opposite direction. Similar to the situation on a screwed spindle nose, where the chuck will happily unscrew when you go suddenly from forwards to reverse.

In the case of the scroll, it's switching from reverse to forwards where the problem occurs.
In my case, I was commissioning, with nothing clamped in the chuck, and trying to see how repeatable the reversing position would be (about 0.5mm before any attempts to refine the mickey-mouse lashup). The only symptom was a funny noise which sounded as though it came from the front spindle bearing. Picture yourself leaning down, (putting your head inadvertantly in the line of fire) to try and pinpoint the noise, as you flick the fwd-reverse switch with your thumb....

The jaws may open a considerable distance on each occasion, about 5mm in my case, and spinning at this speed they're essentially invisible. When I stopped the trial, they were almost fully out. This was a heavy industrial chuck and each jaw weighs about as much as a 1/2" Jacobs drill chuck.

Apart from the commissioning case or, say, threading between centres using the chuck only as a catchplate, when the jaws are not clamping anything, it's possibly even worth considering this scenario when you decide how tightly to do up the jaws of a job you'll be threading with rapid reversals.
I'm thinking particularly of threading, say, thin walled tubing, where there's little resistance to allow building up a decent amount of clamping pressure, and it seems to me the jaws could very easily release the work.

If I do jobs like this I'll either dial in longer decel and accel parameters, or make a closefitting plug for the work. (Note to self, DO NOT FORGET!!!)
Title: Re: Swingup external threading tool
Post by: John Stevenson on May 15, 2010, 07:28:51 PM
But this is with nothing in the chuck.

I use my swing up tool all the while now and I do a lot of screwcutting. Because the TOS is a dream to use with this tool I basically screwcut everything and finish off with a die if I have one or use the Coventry die inserts.

Last week for example I did 24 special M18 x 1.5 pitch bolts 60 mm long.

At no time have I had the chuck jaws come loose because of the quick reversal.

John S
Title: Re: Swingup external threading tool
Post by: troup on May 15, 2010, 08:51:04 PM
I'm relieved to hear that, John

Just to clarify, though: that contingency (inertial loosening when a lightly gripped part is reversed) was not the main thrust of my warning, nor was normal screwcutting.

What I wanted to alert people to primarily was the situation which might arise during COMMISSIONING or troubleshooting of any instant reverse facility: lots of reversals, dry running (so pushing the envelope speed wise) with nothing gripped in the chuck.
Title: Re: Swingup external threading tool
Post by: Artie on May 16, 2010, 05:31:46 AM
I hear whAT YOU ARE SAYING BUT AT THE SPINDLE SPEEDS AT WHICH SINGLE PPOINTING IS CARRIED OUT, THIS PROBLEM IS PRETTY UNLIKELY...oops sorry damned caps lock..... :doh:

Btw, thanks to Bogs, this item is HIGH on my list of tools I need to make ....

Cheers Rob T
Title: Re: Swingup external threading tool
Post by: troup on May 16, 2010, 07:51:47 AM
I hear whAT YOU ARE SAYING BUT AT THE SPINDLE SPEEDS AT WHICH SINGLE PPOINTING IS CARRIED OUT, THIS PROBLEM IS PRETTY UNLIKELY...oops sorry damned caps lock.....

It happened at only 250rpm or thereabouts on my lathe, which is well within the single pointing speed range for a fine thread, even on a totally manual lathe without any fancy bits and pieces. And it happened emphatically. not tentatively, although I reiterate that the chuck was empty.

I'm puzzled you would say that in any case; the only reason single pointing on manual lathes is done so slow is the human factor. From a process (and particularly finish) point of view the traditional speeds are woefully sub-optimal, especially for carbide.

To me the main attraction of this flip-up tooling idea is single pointing at speeds more like CNC than manual lathe practice. This in turn is the main reason CNC threads (particularly in gummy materials like mild steel or alu) are so much shinier in their finish, and when I saw that fantastic video of John Stevenson's I suddenly realised we mortals could have that too !
Check out the finish on John's photo, also (not the crummy material from the second, LH thread (?) test, but the first.

It's my hope, which I'm a few more hours of spare time from of testing,  that (providing reversing is accurate and automatic) it should be perfectly feasible to single point at speeds unthinkable on any manual lathe short of a Hardinge HLV with a highly sophisticated single tooth dog clutch. This is dedicated to providing an adjustable, reliable and automatic reversal cycle, specifically for singlepoint threading, even up to a shoulder. The manufacturers cheerfully suggest this facility should not be used at over 800rpm, or 1000rpm, I forget which...

A new Hardinge is about USD50,000, or 15,000 for a Taiwanese copy.

Compare this with:
Flip up toolholder: a few hours or days of work, depending on sophistication
Auto reverse sensing/switching and trip dogs: if you already have a VFD: maybe the same
In my case, I need to make a 'Dead man's pedal' for control and safety reasons (the inverse of a foot brake), and that's just about done.

I'd like to say a huge thank you  :beer: to the people who blazed this trail; to the guy from another forum (Mike Cox?) who revived (or independently reinvented) the idea, to the guy who brought it here, to the intrepid early adopters who so generously and inspiringly and thoroughly documented their investigations and implementations, including Darren who brought the good news from Ghent to Aix (ie posted on the PM forum, bringing it to a new audience again, myself included.)

I'd even like to thank the muppet who took umbrage at a perfectly reasonable response to his plea for drawings -- for having the decency (or truculence, or whatever) to leave the field before his hissy fit could give rise to any temporary tensions in the exemplary public-spiritedness of this forum.
Title: Re: Swingup external threading tool
Post by: Bogstandard on September 21, 2010, 08:03:36 AM
I have now finished reading the rest of this topic, and it seems to have generated a fairly large following and comments on other sites as well.

But I have noticed there are people who think nothing of changing the basic design and calling it OK to work with, then calling it their own 'new' simplified design.

I am not boasting, but I have had a very deep grounding in basic engineering design, which it seems a lot of people haven't, and in the unshown background, while developing this tool, lots of calculations were used to make sure the original design I did turned into a simple build exercise, where almost anyone with a bit of machining knowledge could make one, and get a tool that would work, and last almost indefinitely.

What has been done by other people, is basically doing away with the little block under the nose of the tool, the one that stops the tip of the tool swinging side to side, and are relying on a large washer around the rear pivot point instead.

WRONG.

Little would you believe it, that little block is one of the most important bits of the whole setup.

Without going into deep calculations about moments and stresses, and to explain it in easily understandable terms.

The block is there to take all the load of the side cutting action, and not allowing those loads to reach the pivot bolt. By doing away with it, that side load is instantly and drastically increased by the moment of the length of the swing arm and cutting tool, and is very likely going to cause the pivot bolt to break at the shoulder where the thread screws into the main block. Maybe, with dire results.

The things I show usually do take a lot more thinking about than you ever see, plus also I do try to simplify things so everyone can understand it.

So please, if you are going to change the design, look to the possible consequences that might happen before doing so.
 
I don't give a rat's arse about someone taking a design of mine, or anyone elses, but what I do object to, is people taking a proven and safe design, and modifying it to where someone just might get injured.


Bogs
Title: Re: Swingup external threading tool
Post by: Boucher on September 23, 2010, 12:09:45 PM
I don't give a rat's arse about someone taking a design of mine, or anyone elses, but what I do object to, is people taking a proven and safe design, and modifying it to where someone just might get injured.



--------------------------------------------------------------------------------

If you don't try it, you will never know if you can do it.

Somehow these two statements seem to be in serious conflict. I have no personal intrest in turning left hand threads and I doubt that the key is needed for right hand threads. As stated, "If you don't try it, you will never know if you can do it.

For a really simple swinging tool a dedicated tool post rather than the quick change holder appears to hold the advantage in simplicity and rigidity.

The description and detail of the cutting the quick change holder is very well done and should be preserved as a separate stickey for others to copy. John Stevensons inverted design and the way he makes the tool blocks in long strips makes one think about doing that for these tool holders as well.

This swinging thread tool is one of the best work saving shortcuts that has come down the road in a long time. If your machine has the features to use it you should try it.

 
Title: Re: Swingup external threading tool
Post by: 75Plus on September 23, 2010, 02:04:56 PM

But I have noticed there are people who think nothing of changing the basic design and calling it OK to work with, then calling it their own 'new' simplified design.

Bogs

In all honesty John, I believe you took Mike Cox's design and made your "New and Improved " version to satisfy YOUR tastes. Not everyone feels the need for a "Rolls Royce" model so they build themselves a "Ford" which serves their need. It should be their choice and, if they choose to post their results, that should be OK also.

Joe
Title: Re: Swingup external threading tool
Post by: Bogstandard on September 23, 2010, 06:18:19 PM
Joe,

As I stated, they can do whatever they like with the design. Plus if you read this post thru, you will see where I posted a few pics about one that could easily be made, basically from bits and pieces in the average shop.

My gripe is where someone just comes up with an idea, not necessarily based on my design, and that design is basically flawed and so could become the cause of an accident.

When you post on a public site such as this, you will come under the scrutiny of everyone, so you must expect the criticism as well as praise.

If you do show what you have made, you had better make sure it is basically bombproof regards to safety. Because if someone should take on your idea, and make a copy of your flawed design, then you must be willing to take the responsibility if something does go wrong. Because if it does fail, and something nasty does happen, then where will the finger point?

Some people have no idea or common sense when it comes to safety in design, if it works, they are happy, with no thought of what might happen in the future when it fails. It is up to people who do post ideas on here to make sure no one can come to any harm if they follow your actions.

BTW, I used to build custom Rolls Royces, and I would have a Ford any day, well not really a Ford, almost anything else, but you get the point.


Bogs
Title: Re: Swingup external threading tool
Post by: dsquire on June 07, 2011, 03:46:30 PM
Hi All

I am going to bump this thread up as there seems to be some new interest in this tool.  :D :D

Cheers  :beer:

Don

code
16982
Title: Re: Swingup external threading tool
Post by: snoopdog on June 07, 2011, 05:14:23 PM
I never did understand it for threading, is you want to slam the lathe in reverse why can you back off the cross slide too? I can thread normal at a fast rate.

Its kind of pointless in my eyes, I see nothing to be gained but some tool flopping in the wind. Bye bye rigidity. it might work for a watch maker but I dont do tiny parts, no way would it be of help on the big stuff I do.
Title: Re: Swingup external threading tool
Post by: No1_sonuk on June 07, 2011, 05:55:31 PM
I never did understand it for threading, is you want to slam the lathe in reverse why can you back off the cross slide too? I can thread normal at a fast rate.

Its kind of pointless in my eyes, I see nothing to be gained but some tool flopping in the wind. Bye bye rigidity. it might work for a watch maker but I dont do tiny parts, no way would it be of help on the big stuff I do.
Did you read the thread, including watching Bogs' videos?  In one he makes a quite hefty thread.
"Slam the lathe in reverse" isn't the way to do it either.  Stop, then reverse is.
Title: Re: Swingup external threading tool
Post by: John Stevenson on June 07, 2011, 06:03:20 PM
no way would it be of help on the big stuff I do.

I only do big stuff and it works for me, in fact I no longer thread any other way.

John S.
Title: Re: Swingup external threading tool
Post by: Ned Ludd on June 07, 2011, 06:34:35 PM
Please define "big stuff".

It may only be small in your eyes but today I was cutting several M12 by 1.5 threads in mild steel at
about 200 RPM in about a dozen or so passes. Yes, I know I could have turned the speed up but my
 reactions ain't what they used to be. :(   I could have taken less passes, by increasing the first
few passes, but I wasn't in any hurry. If it can work on that it will work on anything!
As an old saying goes "don't knock it, till you try it", they really are a very useful tool and if built to a reasonable standard are quite rigid.
Ned
Title: Re: Swingup external threading tool
Post by: No1_sonuk on June 07, 2011, 06:47:37 PM
I've done up to M10 x 1.5 - not needed to  go higher yet.
Title: Re: Swingup external threading tool
Post by: DaveH on June 07, 2011, 06:54:14 PM
Hi,

Now lets be nice :D :D :D

 :offtopic:

My problem is I don't have a brake on my lathe :(

So stopping in the same place is a little hit and miss. :doh:

Any thoughts

 :beer:

DaveH
Title: Re: Swingup external threading tool
Post by: John Stevenson on June 07, 2011, 06:56:27 PM
Biggest so far this week is 4" gas thread, that's 4.450" OD x 11 tpi

Smallest was M16 x 1.5

John S.
Title: Re: Swingup external threading tool
Post by: AdeV on June 08, 2011, 02:47:34 AM

My problem is I don't have a brake on my lathe :(

So stopping in the same place is a little hit and miss. :doh:


I have the same problem - although the lathe does have a brake, it barely works, so - like you - stopping in the same place required a degree of co-ordination and reaction times that I simply don't posess. Not to mention the fact that all the bits of my lathe have so much inertia, that it's probably quicker for me to cut threads in the "traditional" way.

If I ever get a lathe like John Bogs's (which stops stone dead the instant you hit the footbrake), then for sure I will build one of these threading tools.
Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 06:46:41 AM
Ade,

Thanks for the reply.

Even the normal way is a bit tricky if I only have a mm or two to play with. :doh:

Strange you should mention John's lathe, mine is the same, only a much earlier model 1990 ish.

No brake though. I can and do cut threads just a bit slow. :(

I was just wonder how others get on without a brake.

Also does anyone use a "swing up" or simular tool without a brake.


DaveH
Title: Re: Swingup external threading tool
Post by: wheeltapper on June 08, 2011, 06:57:49 AM
I use my one on a Chester Comet minilathe , that hasn't got a brake and the lowest speed is 100 rpm.
I cut a runout groove with a parting off tool and I seem to manage.

when I tried this tool out I cut a 1.5 thread on a lump of 1" mystery steel and using the forward and reverse buttons it made a reasonable job at 200 rpm and my reactions aren't as sharp as they were. I say reasonable because it was a grunchy bit of metal and I didn't use any lube.

I couldn't see any deflection or wobble either.
I like it.

Roy
Title: Re: Swingup external threading tool
Post by: AdeV on June 08, 2011, 07:03:48 AM
100 rpm.

 :bugeye: :jaw:  :bugeye:

I thread at either 35rpm or 59rpm, and I reckon the latter one is a bit swift!

I must admit, I don't cut myself a relief at the end of the thread; I just watch it & wind the cross slide out at the end of the last groove, simultaneously disengaging the drive. It usually works out OK...
Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 07:14:42 AM
Roy,

There is not a chance I could accurately stop my lathe within 1 mm. I have even tried to (measure) how far it will run after the stop switch at different speeds. Even thats not constant (depends on the depth of cut / type of metal).

Cutting a 1/2" thread up to a shoulder (1mm) can be a bit tricky.

Really not good for "m'nerves" :doh:

I can do it but what a pain. :hammer:

A brake and this type of holder seems a good way to go. :)

Any more thoughts.

DaveH



Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 07:24:06 AM
Ade.

I have 60   90   200rpm

If it is a bit tricky I use 90 rpm otherwise 200rpm.  The 60 means I have to change pullies - danm I'm lazy :doh:

And if it is really really tricky I turn the chuck by hand - that's slow :D

and it makes my arm ache :(

DaveH
Title: Re: Swingup external threading tool
Post by: AdeV on June 08, 2011, 07:33:35 AM

And if it is really really tricky I turn the chuck by hand - that's slow :D
and it makes my arm ache :(


Could you make/obtain a crank handle that goes in the back of your spindle? That would make turning the lathe easier; and would also mean you could turn right up to a shoulder with excellent accuracy. It'd also be great with a swing-up holder, because you're in total control of the speed & direction of the stock; so you just wind forwards to the end point, backwards to get off the thread, move the cross slide (or top slide, depending on how you're cutting) in a few thou, rinse & repeat.
Title: Re: Swingup external threading tool
Post by: No1_sonuk on June 08, 2011, 08:18:28 AM
I use my one on a Chester Comet minilathe , that hasn't got a brake and the lowest speed is 100 rpm.
I cut a runout groove with a parting off tool and I seem to manage.
Same for me, but Chester DB7VS (a 7x12 size machine).
Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 09:01:54 AM
My lathe is the same as Chester Crusader only without the bells and whistles and 1990 ish,

The hand crank is a good idea :clap: - only in the past when I have looked at it - seems it maybe a bit of a stretch. :doh:

I think I must have short arms :lol:

Thank you all, I really appreciate your input  :thumbup:

I'm going to look at the hand crank again.

DaveH
Title: Re: Swingup external threading tool
Post by: krv3000 on June 08, 2011, 09:13:19 AM
HI all well i have cut threds on my lathe witch is a emco compact 8 by hand crank i tride to cut a thred the way it tels you in the manuwel and it all went rong the lathe has a cluch so wat shud hapen is you hit your stope and the cluch cuts in and all stops but this did not hapen and at furst i thort i wood have to by a new leed scruw untill i fawnd out that ther is a sacrifishel pin that gives way  at the end of the chaft   from bob
Title: Re: Swingup external threading tool
Post by: wheeltapper on June 08, 2011, 10:51:57 AM
A hand crank is definitely the way to go, especially for short threads up to a shoulder, there's just no time to get into the swing.
I made mine so I can fit either a handle or a change wheel for indexing, there's some pics on here somewhere.

Roy
Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 11:09:01 AM
Roy,

Thanks I'll have a look :D

 :beer:

DaveH
Title: Re: Swingup external threading tool
Post by: DaveH on June 08, 2011, 11:18:11 AM
Roy,

OK I found it - expanding mandrel, the way to go :D :D

Thanks

 :beer:

DaveH
Title: Re: Swingup external threading tool
Post by: doubletop on June 13, 2011, 06:22:06 AM
I am going to bump this thread up as there seems to be some new interest in this tool.

Don

Mike Cox has an article on his original design in issue 178 of MEW and has quoted this thread which is probably generating the interest.

Pete
Title: Re: Swingup external threading tool
Post by: David Kirtley on October 23, 2011, 07:55:18 PM
Well, I have been reading this thread for a while and wanted to try my own version.  It is a work in progress but I thought I would look for some feedback from people that know more. I am just starting out and this was my first attempt. I figure it was better to actually make something instead of just swarf.


(https://lh5.googleusercontent.com/-FFf8IO73X-0/TqSX-5qRsFI/AAAAAAAACAc/JUHSqaJzi3c/s144/DSC00849.JPG)

I was under a bit of a constraint fitting it on a little mini-lathe QCTP (A2Z CNC).  Instead of a key, I just plowed a groove for it to fit in to keep it from moving left or right.

Here is with the tool holder in place It gives me about 0.25 room to adjust up to meet center height. The bottom of the tool holder is a bit thin but all it will be holding is the locking screws. The force will be on the main holder base. I left that as thick as I could.:

(https://lh6.googleusercontent.com/-Y38Cq0x3q9o/TqSXSWQcmDI/AAAAAAAAB-8/pKTF2mA_aDE/s144/DSC00855.JPG)

I milled a bit away on the swing arm to keep it from interfering when it swings:

(https://lh6.googleusercontent.com/-egVtad-zTVc/TqSYJpsHr6I/AAAAAAAACA8/FLJiYSPWyzA/s144/DSC00852.JPG)

I might put a shoulder bolt for it to swing on but for right now, I just have a cap screw. I doubt that my poor little lathe could develop enough power to snap a 1/4-20 screw.  I have not decided yet where I am going to trim off on the front and back. Right now it is way to long front and back so I had enough wiggle room to shape and finish.

(https://lh5.googleusercontent.com/-xgD6qZmuq4Q/TqSYI6LdqRI/AAAAAAAACA0/2q3HdJchOfg/s144/DSC00851.JPG)

Next up will be drilling for the lock screws for the tool holder and the adjuster.
Title: Re: Swingup external threading tool
Post by: andyf on October 24, 2011, 04:09:07 AM
Nice one, David  :thumbup: .

Might the width of the support to the left of the swinging part get in the way if you want to thread close up to the chuck jaws? I think that's why Bogstandard, when he reworked the original design, used a key underneath. Of course, if you only want to do RH threads, you don't need any support on that side (or a key) at all.

Screwcutting a shoulder bolt, with a plain shank to act as the pivot, should be no problem now!

Andy

 
Title: Re: Swingup external threading tool
Post by: David Kirtley on October 24, 2011, 10:56:19 AM
Hi Andy,

I thought about doing it like bogstandard but I was under one additional constraint. My tiny QCTP doesn't have much room in the vertical direction.  I went down as far as I thought I could get away with under the cutter holder to get the cutter height below the centerline. 2.25mm just doesn't give me a lot of leeway to put in a key. I was already down to 6.8mm for the ledge for it to ride on and didn't want to go any thinner to keep it from flexing while cutting. For a real practical version, I would be much better off making my own toolpost that rides on the compound rather than using the QCTP or even move it all the way down to the cross slide. Then I could just go ahead and use big cutting tools and not even worry about flexing.

Not quite that worried about chuck clearance. I mainly use an ER32 collet holder on the faceplate that doesn't have as many spinny bits.

Honestly, it was just a fun exercise to practice cutting to dimension and play with a different approach.
Title: Re: Swingup external threading tool
Post by: andyf on October 24, 2011, 11:50:51 AM
Hi Andy,

Honestly, it was just a fun exercise to practice cutting to dimension and play with a different approach.
Hi David,

Well, out of something done for fun, you've produced a useful bit of kit! I look forward to seeing what you get up to when you are being serious.

Andy
Title: Re: Swingup external threading tool
Post by: David Kirtley on October 24, 2011, 12:20:28 PM
Here it is in a bit more presentable state. All I have left to do is the set screws for the cutter and the threaded post for the adjuster. I might pretty it up finish wise but for now, I am staying with it. I guess I will stop by Harbor Freight and pick up one of their set screw sampler packs for some fiddly bits.


You can see where I have trimmed it off with a radius to give a bit of clearance.
Title: Re: Swingup external threading tool
Post by: David Kirtley on October 29, 2011, 09:36:13 PM
Just an update.

I drilled and tapped for the locking screws for the cutter and the adjuster. Of course they were out of the cheap assortment of set screws at the discount store, so I just put some cap screws in for now. I also need to pick up a couple nuts for the adjuster.

Well, the only misfortune was one of the set screws is offset (Yes, I broke off the tip of a center drill)

Anyway, after setting the height by hand since I don't have an adjuster, I grabbed a piece of junk AL from the ziplock I keep near my lathe and tested out cutting threads. Swapped out all the gears to set up for M1 threads.  I do have to say, it exceeded my expectations. Everything worked as advertised and threading was a simple relaxing exercise.
Title: Re: Swingup external threading tool
Post by: madjackghengis on October 30, 2011, 09:54:48 AM
Bernd,

I have a shoe brake system on my machine, complete with a drum, just like a car, it is very efficient. I thought this was a lot of backlash on my machine since I had set it up, so just how bad is yours?

Bogs

John,
The old Logan I've got doesn't have a brake on it so I'd need to run it real slow for one thing.

Second, when I reverse the machine the chuck will start to turn and at about a 1/4 of a turn of the chuck the lead screw will finally start to turn. Then after the chuck has made almost a full revolution backwards the carriage will finally start to move. Have I made this clear enough to understand? That is one reason I think this tooling will not work in "my" machine.

I'm sure that the gears on the headstock probably have more backlash than they need. As far a the lead screw is concerned, I'll have to take a closer look.

In the mean time I guess I'll just have to resort to turning the cross slide out of the way.

BTW, I'm amazed at how nice that tool follows the thread groove backwards. Great job.

Bernd

  I too have an "old" ten inch Logan, and Bernd's description and the backlash in my '48 are about the same.  I built a Metal Lathe Accessories quick retract tool post twelve or fifteen years ago, and found it eased threading enormously, and use it for most of my threading, but compared to what I see with your tool setup, I'm working way too hard. 
      I had to turn a ten mm by 1 mm thread without transposing gears a few months ago, and figured one of my feeds was almost perfect, so I set up as per normal for threading, but with the feed clutch tight, retracting the tool bit at the end of the cut, and then reversing the lathe, and the thread came out perfect, worked perfectly to pull a very stubborn power steering pump pulley back onto the shaft, with the cut thread fitting into the shaft by hand snugly, but by hand all the way. 
      With your tool set up, I would have merely had to reverse the lathe, no retract, and set more feed.  I have watched you with this tool, and watched when you were working on one some time ago as well, and I think the greatest worries you should have is making one to fit say quarter in tool bits, or smaller, so they are light enough to lift with the smallest of threads.  I've watched the tool tip while reversing the lathe with it retracted, and while the tip ends up close to being in the middle of the thread, and not the cut groove, but I suspect the tool would ride there fine in reverse, and I'm going to try this. 
      The quick retract is a work of art, and works great, but if I can cut my threading time in half, I'd be very happy.  I'm also looking for a place to attach a brake, I have long wanted one, but never got around to doing anything about it.  Thanks for going through all the effort to show this off in all its capacity. :jaw: :beer:  Cheers, mad jack.




**Edited by Stilldrillin. To show Jack's posting, clearer........
(If I've got it wrong Jack...... Let me know!).
Title: Re: Swingup external threading tool
Post by: David Kirtley on October 30, 2011, 10:11:50 AM
The largest bit mine can take is 1/4 in. I was actually switched to using an even smaller bit on the second test. By the time you add on the weight of the swing arm and the lock screws, the weight of the bit doesn't really make that much difference. If it doesn't prove to be enough to overcome friction, you can always add a weight or a spring.

The only thing I can see as a possible point of failure is for reversing with the bit engaged in the work piece and the pressure flaking off a chip of carbide.
Title: Re: Swingup external threading tool
Post by: abinitio on May 19, 2014, 10:42:47 AM
I would like to make this. Drg. with Dims would be usefull. some pics would be good regards AB
Title: Re: Swingup external threading tool
Post by: Arbalist on May 19, 2014, 12:26:30 PM
I would like to make this. Drg. with Dims would be usefull. some pics would be good regards AB

Have a look here mate:

http://www.modelenginemaker.com/index.php?topic=858.msg9461#msg9461
Title: Re: Swingup external threading tool
Post by: drmico60 on May 19, 2014, 01:53:06 PM
Hi AB,

Also have a look here.

http://mikesworkshop.weebly.com/swing-up-tool-holder.html

I have also designed a swing tool for internal threading, see:

http://mikesworkshop.weebly.com/internal-swing-toolholder-for-threading.html

Mike