A thing.....

[Darren]

Ok, like I need it, I have started something new whilst I wait for some killer drill bits for my other ongoing project.

I'm not going to tell you what it is for a change, be interesting how long it takes for someone to call it out. It's hard as nails, err, no that's not right. It's way harder than that.
So I decided to make something that didn't need any threading....!!

I wanted to do some milling, well I've wanted to do that for some time, but now I can 

I was really needing some larger stock, but this will have to do for now.

No idea what it is/was, but it's heavy. Around 60mm dia.



Chopped a piece off the end



Tidied it up in the lathe, now the halfshaft I last used was hard, this was much harder...I'm talking a lot harder and it was right through as well. No soft core in this one. My band saw cut the halfshaft, it wouldn't touch this.....



Like the halfshaft material the finish was excellent, bit tough on the carbide tips though....

Next job was to drill it off center, 5mm in this case.



Then bored to 28mm to a depth of 1,25", yes I know mixing measurements. Been around John too much 



Now to part it off, I got down to a 10mm core and tried to hacksaw as my parting tool wasn't long enough. All it did was make a scratch and take the teeth off the blade. Tried a new blade and it did the same thing. That's how I know it's hard to the core 



Anyways, I modified one of these into the parting tool above, That sorted it. The tough guy just melted when poked with this.



Cleaned up the parted face and we have this, that's the lathe work done for now. Next stop the miller

[Darren]

Cor, nobody guessed what it is yet? 

Better put some more pictures on then....

So now on the miller for some flatwork, those of you with keen eyes may spot the cutter has a tooth missing. A fair old chunk of it gone too. My old mill was good at doing that if you showed it some steel. Almost every time I used the thing 

HSS is never gonna survive cutting this lump so this carbide end mill was used. I do have a couple of good ones I could have used (thanks mate  )
However I was not going to chance them on this. One because is was a hard unknown material and two, because I'm used to breaking cutters 

So here we go, looking good so far, cutting very nicely.....so far........



Yep still cutting smoothly......fingers crossed....



AND IT'S STILL GOING SMOOTHLY.......
I'm not used to this....



And that's where I finished off tonight......

Considering how hard this metal is I think the miller is behaving very well indeed. Giving a really smooth finish, no snapped end mills and it's not even complaining...

 

[bogstandard]

Darren,

I think this job would be a very good candidate for trying some coolant on it. I can almost guarantee the cutter will be well and truly knacked by the time you have finished.



BTW, I think I now know why you were having so much trouble with the old mill. My guess is that it was an old imperial machine, and everyone knows that you should only put the cut on for metric cutters in mm instead of thous.
The cutting angle was totally wrong for removing imperial chippings and so the cutters duly snapped off because the flutes got choked with imperial swarf. 


Bogs

[bogstandard]

Darren,

I have just reread the whole post, and by the looks of it, your bit of metal seems to be a drawbar or large pivot pin. If it is, then that will be some real tough material. Designed to take very high shear loads without bending or breaking.

yes I know mixing measurements. Been around John too much

Measurements are only there to give a guide to finished size. Use what you need until you get very close.

These are imperial terms.

Tweak - between 0.002" and 0.005"

Gnat's cock - 0.0005" to 0.001"

A 'sniff' or 'snifter' - 0.0001" to 0.0004" (as in 'a couple of snifters' - 0.0002")

For metric, I suppose you translate the above to French.

'Il or Elle tweak' (verb, as in 'I tweaked a couple of thou off'), 'Un Gnats cock', has to be masculine, a lady gnat doesn't have one. Then 'Le sniff' masculine, 'La snifter' feminine, both have noses.

Bogs

[HS93]

I work in Ferkins , they come in units of two  two ferkin big two ferkin small   two ferkin heavey.. etc   



ooops that's me banned
oh well it was good while it lasted

peter

[Darren]

Did I say it was "ferkin" 'ard.

There, a reference point for all to work from 

Hi John, no I don't suspect the cutter will be too clever by the time it's done on this. That's why I used a knackered one. Call it a learning curve.....
I'm learning how you guys managed to cut such great stuff.

But at least if the miller can do this it should be great for sane work... My old miller would have snapped this cutter clean in half by now and that's no exaggeration.
I'm suspecting a worn bearing or something.

Yes, a draw pin/bar looks a good candidate from the shape of it.

It's got to go on another machine to finish it off. The miller, even though it's doing a grand job is only removing bulk quickly.
I could have done this on the shaper with a carbide bit. It would have taken days...... The shaper will have to finish it though.....another clue 

[NickG]

This has got me stumped Darren  , what on earth is it?! 

[Darren]

You ALL know what it is.......

New post coming soon, you'll get it then.........

[Darren]

Back to the thing again tonight 

Time for a sitting at the shaper now. I do like using the shaper, so relaxing compared to other tools. Can even go and make a cuppa whilst it's going as mine has auto stops fitted.

Using my lathe index tool here, the finish is more to my liking than the mill gives...



Checking it's all square, yep looks good enough to me



Now then, another clue as to what it may be. I needed to cut some 60 degree dovetails. I don't have a milling cutter for this job so I'm going to use the shaper. After all, it was designed to shape things 
I needed a cutting tool, the index was no good as it's angle was over 60deg. I guess normally Iyou'd grind up a HSS blank to the shape required. But this metal is hard, too hard for HSS. It was destroying carbide tips at a rate of knots.
I found this, it stated 18%, I presume that meant HSS with 18% cobalt?
18% is a high ratio, my other ones are 5%. Maybe it would last the course, only one way to find out....

I used a threading tool gauge to determine the 60deg angle. Anything less than would be ample, this turned out to be 55deg.



I set the top slide over to 60deg on the shaper and started cutting



A little while later, like an hr later.....and we have this



Turn it over and machine the other face



Shaping finished and now off back to the miller, drilled another hole and tidied the edges up with a chamfer tool..



Right then, have you guessed what it's to be yet. You should have by now 

A quick clean up and it's looking rather good...



Incidently, I dropped it on the floor. Took a chunk out of the concrete, and I though oh no !!!

Picked it up, wiped the concrete dust off it to look for the damage......not a mark on it....

I was going to make two of these, but making just this one has been a task. The metal is simply too hard, it's destroyed tooling, not one but about five carbide tips and one carbide milling cutter, two hacksaw blades, a bandsaw blade and my scribe !!!!!

Well ok I can sharpen the scribe....

I think I'll leave the rest of this bar for something else, something much simple.......like a rusty bar or sumut....

[sbwhart]

Is it a tool post ?

Nice bit of machining by the way, 
That stuff really looks hard 

Stew

[Stilldrillin]

I know what it is, now! 

I think....... 

Well..... 


Well, I would...... If it was made of brass/ bronze...... 


Hmmmmm.........


David.

[bogstandard]

Darren,

You are doing a sterling job murdering this bit of metal, it looks like you have got the hang of cutting stuff to the shapes you want. A very well done for that.

We've just got to get the quantity of tool kills down a bit. But I hope that will come with experience and the use of lube/coolant.

I know it is messy and gets everywhere, but it is either that, or your pocket will start to feel the cost of all the cutting bits. To such an extent, it might be cheaper to buy the parts rather than making them.

As soon as you start to get onto harder materials you must consider getting some sort of coolant on there, before tooling attrition gets too much to bear.

I will be looking at the spray jet unit I have just been given within the next few weeks, maybe that should be considered the way to go.

John

[Darren]

Well done Stew, yes it's a QCTP, 

I have to be honest, I wanted a bigger one than this. But it is at least bigger than the one on my mini lathe. I may just end up cutting the dovetails down a touch to the same size as the mini QCTP. Then I can use it's tools on both lathes.

Also I will be ordering some steel stock and having another go. I'm hoping mild steel will be a lot kinder to tooling and be a bit easier to use. Having said that, even though I have killed about £30 worth of tooling, a block of steel would have cost me almost that with postage. So it's swings and roundabouts.

The aim was to have a go at cutting dovetails, I think it's worked rather well and I'm fairly pleased for a first attempt. Bit of a learning curve and lots of thinking. Didn't all go to plan of course but I'm learning.

For the dovetail I cut a tool to 60deg, wrong, let the shaper deal with the angles and the tool the cutting. I discovered I needed less than 60deg on the tool.
My shaper is not marked for 60deg, only goes to 50. So some re-marking was required there. BTW, at that angle it's a long way over and you start to run out of room. 45 might be a better choice here, but existing tooling is 60 so it had to be.

I was inspired by this chap...
http://homepage3.nifty.com/amigos/qctp/qctp-e.htm



http://homepage3.nifty.com/amigos/qctp/s-img_8081.jpg[/url]

Have a look at the rest of his site, very talented chappie

http://homepage3.nifty.com/amigos/index-e.html

Now then, I need to buy some steel stock, but what and from where? There are so many grades to choose from. My biggest fear is spending a ton and ending up with material that machines like poo...
Some help chaps if you will, I'm not finding much at the scrappie other than small pieces.

[bogstandard]

For what you are doing Darren, I personally would use EN1A steel.

I hate quoting numbers, but that is recognised everywhere as a lightly leaded, free cutting mild steel.

If you can't get an easy smooth cut, and a superfine finish on that, you should take up knitting.

John

[NickG]

Looking good Darren, that is a project I wanted to do too but think I may just buy one and concentrate on making engines, otherwise I'll never get anything done! 

[shoey51]

very nicely done
I wish I had those skills

[Darren]

Thanks for the kind comments chaps. Who said skill?

Wrong place for that, I'm only learning and bumbling along as I go.

John, I'd be interested in how that misting unit gets on when you have it sorted. I did use WD40 on this, but that's not the same is it.

I would have done more tonight, but I'm in too much pain this evening to go into the workshop. I'd have a job to walk there never mind stand at the machines for an hour or so.
It comes an goes, old bike injury, lost my right hip about 20yrs ago. Completely shattered it, was too young for a hip replacement apparently. Can't do it till you have stopped growing.
It was either leg off or make do with a badly repaired hip, if you could call it even that. I chose the latter, like you would....

Anyways, I'm rambling no, must be getting old or sumut.....

[Darren]

Moving on a little today, time to make some more parts to go with this.

Starting with the cam I used a piece of 30mm alloy bar. Turned it to 27mm the same as the bore in the main block. I chose 27mm because a have collet in this size.
See, I've started doing some forward thinking at long last !! 



Next task was to machine an off center cam for operating the piston. A distance of 2mm was chosen which happened to be the size of this piece of scrap. So it was used to measure the offset.



That's the cam done



Turned it around and stuck it in that 27mm collet I mentioned earlier to machine the head.



Off to the miller to drill and tap for a handle, I chose a 6mm thread.



Now we need a center spigot. Selected a 20mm bar for this and duly turned it down on the lathe.
This fits down the center of the cam and is slightly longer, half mm would do. This allows the main block to be tightened down without pinching the cam unit.



Next up is the piston, nothing fancy, it's just a small slug. Mine has a hole down the center simple cos it was already in the piece of scrap chosen.
It could do with a couple of o-rings to hold it in the main block to stop it falling out. I'll get to that when I can find some and put a couple of locating groves in the piston to hold them in place.



Sum of parts so far, used a 6mm bolt for a handle for now till I make something better.

[sbwhart]

You're making a real nice job of that Darren like how you thinking ahead and using stuff you've got arround you 

What size tools wil it take ?

Have fun

Stew

[Bernd]

Nice looking bit of kit as you Britts would say. Looking good Darren.

You are using aluminum for the cam. Won't that gaul up are a few uses?

Bernd

[Twinsquirrel]

Looking superb, wish I could yhink things through as well as that.

David

[Darren]

Thanks guys,

Stew, This lathe won't take big tooling as the compound slide is quite high. I doubt it was designed for such as it's really a "second operation lathe" and used a sliding turret.

I tend to use 10mm size same as my mini lathe, but both could take 12mm easily. You could make toolholders for the QCTP to take larger tooling though I would think. I'll prob have a go at some time.

Bernd, yes I know, it might, have to wait and see. If it does I'll just make another in steel. It wasn't hard to make. I just didn't have any steel at the time to make it from.

David, there is nothing difficult here. Even the dovetail could be made on the lathe.
If I were to do it again I'd get a dovetail cutter for the miller. It would be much simpler to keep everything in line. As it is my effort is slightly out. But it works fine.

What I need to do next it adapt it so that the tooling drops on center for both lathes without adjustment. I know how I'm going to do it 


Some more pictures...

Look John, you'll have nightmares tonight 
I'm using it, first thing I noticed is how true the chuck is. Superb !!!
Second was how noisy it is, I'd forgotten...

Altering the size of the piston for a close fit


And here it is in action cutting a piece of steel. I cut the dovetail down tonight to accept the mini's tooling.



Another view, see how much I've adjusted the height setting nut, nip the top off the dovetail will cure it...



I'll also make a clamping handle (the top one) so it's better positioned.

Lever forward, released piston



Pull lever back and the pistons fully out. You don't need this much movement, 1/5th of a turn will do to make it nice and tight.



The piston has a good 45 chamfer so that when you drop the tooling in it automagicaly gets pushed back. I guess when I put o-rings on the piston you'll have to push the tooling down.

All in all, it works....

[bogstandard]

Very nice job indeed Darren, your bits don't look too bad either

I was wondering how long it would be before you tried it out, hope it comes up to your expectations.

John

[Darren]

John,

One of the reasons I made this tool holder is so that I can use the mini lathe more...

Don't make sense eh.....sure it does...

It goes like this, I'm doing a bigger, tougher job, need to use the bigger lathe. But the tooling is on the mini lathe, so I rob and get the job done.

Then along comes a little job, be nice to do it on the mini with all it's features. But he tooling is on the bigger lathe. So I think sod it, too much hassle and just use the bigger lathe.

See, makes sense now dunit 

To be truthful I'm dying to use the mini lathe again, I will think of something to do with it....

[sbwhart]

Good Job Darren
 

Stew

[bogstandard]

Darren,

We all have our own little ideas of getting things done in the shop, so you do it how you want to.
There are no hard and fast rules, so if it suits you, DO IT.

It is always a good idea to have interchangeability, I have done it between my lathe and RT on the mill. It works for me.

John

[Stilldrillin]

Good thinking, and blummin well done Darren! 

 

[raynerd]

Hey Darren, I`ve viewed this topic many times over the last few weeks as I have been concentrating on my workshop and machines and getting everything running as I want it before I go any further with engine builds etc. I have decided to make a QCTP like this and just have a couple of questions. I`m going to be using a round bar of steel rather than a block like you did, only because that is the scrap I found and was given free from the scrap heap!
1. Can I ask about your off centre bore in the main body of the tool post, was this simply to give more clearence when the two sides where taken down to size? I guess if it had been central, once the centre spigot and cam were fitted it would have got near to the edge of the dovetails/sides right?

2. Also, most QCTP have two sides each dovetailed to accept a holder when needed for turning or facing, so a side on the left and a side on the front. I noticed that you have cut flats on two sides but only dovetailed one. Is there any reason you didn`t put a dovetail on the second side so as to gain to working faces?

3. The dovetails themselfs are 60deg or did you use 55deg because of your cutting tool - either way, I mentioned a 60deg dovetail in my latest thread here: http://madmodder.net/index.php?topic=1731.msg17115#new and Jonny gave a reason why it may be more suitable to use 45deg dovetails. I`ll be honest that I`m still not 100% sure why I would have to be more accurate cutting 60deg dovetails than 45deg dovetails but if this is the case, do you think the 45deg would be more suitable?


Anyway, hope you can help. I wasn`t a member on here when you posted this thread so just wanted to say nice job and hope mine turns out as well. I`d be chuffed if it did!

[Darren]

Hey Darren, I`ve viewed this topic many times over the last few weeks

Really....., well you don't seem to have understood it very well cos most of what you wrote is wrong.........

Most of the answers to your q's are in the posts, have another read, slowly this time, and come back with anything you are still unsure of and I'll only be too happy to help..

[NickG]

Chris,

I think the following is right but somebody please correct me if I'm wrong!

On the accuracy thing, I think Jonny is right in that you would need to be more accurate machining the 60 deg dovetails. Pythag tells you that with a 60 deg dovetail, say if you make the dovetail 1mm too wide (exaggerated for purposes of explaination) that will allow the holder to move 1 x tan60 outwards, i.e. 1.73mm. With a 45 deg dovetail, 1mm deviation would allow the thing to move out 1mm, since tan45 = 1.

Also, Jonny mentioned repeatability. When you clamp the holder up with the 60 deg dovetail the variation on how far it pushes outwards is likely to be greater as a smaller component of the force is acting directly inwards. As he said, difficult to explain, will try to knock up a CAD sketch for you tonight if you are still struggling.

Although it never occurred to me before, 45 deg would be better.

Nick

[raynerd]

well you don't seem to have understood it very well cos most of what you wrote is wrong

Correct Darren, I must not have understood because I can`t find anything that explains why you bored in the main shaft off centre and anything stating why you have no dovetails on the front face in addition to the side. You do mention something about your compound slide being high but I don`t see how this effects having a front face for tool holding as well as the side. You do discuss in a little detail the issue of the dovetail angle but not that I understand it. However that said, I think with NickG explanation I understand a little more why 45deg dovetails would allow more error.

So, sorry, I have read and even printed this thread out and I can see you are unwilling as most would be to retype info already printed, but I just can`t find it and would really like to know! No doubt you will be able to embarrass me and quote your posts where the info I require is printed but if it is there, I obviously don`t understand.

Sorry, Chris

Cheers NickG - if you have time for something on CAD it would be useful!

[Darren]

Chris I am not unwilling at all, it's just that it seems you have not read the thread and it could answer most of your questions?

Here goes then...

Hey Darren, I`ve viewed this topic many times over the last few weeks as I have been concentrating on my workshop and machines and getting everything running as I want it before I go any further with engine builds etc. I have decided to make a QCTP like this and just have a couple of questions. I`m going to be using a round bar of steel rather than a block like you did, only because that is the scrap I found and was given free from the scrap heap!

I didn't use a block, I cut a section from a round pin

1. Can I ask about your off centre bore in the main body of the tool post, was this simply to give more clearence when the two sides where taken down to size? I guess if it had been central, once the centre spigot and cam were fitted it would have got near to the edge of the dovetails/sides right?

My round bar was not big enough for two dovetails (you don't need two anyway) and I gained more clearance for machining by offsetting the mounting hole

2. Also, most QCTP have two sides each dovetailed to accept a holder when needed for turning or facing, so a side on the left and a side on the front. I noticed that you have cut flats on two sides but only dovetailed one. Is there any reason you didn`t put a dovetail on the second side so as to gain to working faces?

Explained above

3. The dovetails themselfs are 60deg or did you use 55deg because of your cutting tool - either way, I mentioned a 60deg dovetail in my latest thread here: http://madmodder.net/index.php?topic=1731.msg17115#new and Jonny gave a reason why it may be more suitable to use 45deg dovetails. I`ll be honest that I`m still not 100% sure why I would have to be more accurate cutting 60deg dovetails than 45deg dovetails but if this is the case, do you think the 45deg would be more suitable?

I didn't use 55deg dovetails, I made 60deg ones....it's in the text.

Anyway, hope you can help. I wasn`t a member on here when you posted this thread so just wanted to say nice job and hope mine turns out as well. I`d be chuffed if it did!

Hope that help Chris....

[NickG]

Chris,

I can't see the advantage of having 2 dovetails either, you can just swing it around the other way if you really need to and turn the tool round in its holder.

Nick

[raynerd]

 

Cheers Darren, I know I`m a pain in the ars3 but you`ve helped a lot. I think the biggest reason I looked a t1t is because I said, "I`m going to be using a round bar of steel rather than a block like you did,...! " I said it the wrong way around, I have a block and I know you used round - sorry, that probably did look daft!

I know that you don`t need both front and side faces machined to accept a tool holder but it is a little more convienient. I guess I need to plan out and see what layout is best. I`m still not totally clear about the 45deg V 60deg dovetails but I guess it seems that 45deg would be better/easier. I was actually looking at the QRTP sold by RDG and the clamping mechanism is quite strange - it isn`t just a straight dovetail.

Anyhow, perhaps it is time to get this talking into swarf! Arc Euro actually has some dimension shown for their QCTP so I may use those.

Thanks again, and sorry for being a pain.

Chris

[NickG]

Chris, haven't had a chance to do the CAD sketch to explain yet but I will. A picture is worth 1000 words in this case.

I still don't see how it's any better with 2 on really, you wouldn't leave 2 tools on as they'd prob get in the way.

The RDG ones are dickinson style posts, it's not really a dove tail, bit more like a T slot and the cam pulls a T back towards the main block pulling the T slotted holder with it and clamping against the block.

Not sure if these are better or piston type? 6 & 2 3's ?

Nick

[jgroom]

Hi all.  IIRC 60deg dovetails are preferred for mill tables and such because they have a larger bearing surface than 45deg, larger oil film, better wear, etc.  That being said I don't see why a 45deg wouldn't work fine in a toolholder.  I had a (homemade) 2 dovetail holder on my 9" SB and it was handy, but it was also bulky and a real PITA when working close to the chuck.  It has since been replaced with a single dovetail unit which works much better (and needs painted )

Thanks
Jeff

[Darren]

I had a (homemade) 2 dovetail holder on my 9" SB and it was handy, but it was also bulky and a real PITA when working close to the chuck.  It has since been replaced with a single dovetail unit which works much better (and needs painted )

Thanks
Jeff

That's a very good point there Jeff, you sure can get close and keep overhangs a little shorter without the second dovetail getting in the way.....

[raynerd]

Thanks for that Jeff - very good point and thanks for the pictures.

I`ve just made a start, had an hour cleaning up the scrap steel I just got tonight. I actually was going to use a block but I found a round bar yesterday at the srappy so will use that. It is my first time working with steel and as expected it was much different than working with brass or ally that I have been working with. The top layer was pretty hard but once I`d broke into that it started maching quite easily. Well we`ll see how it goes.... After your thoughts and experiences with a two dovetail holder, I think I`ll actually change my mind at stick to one. Like you said, you simply loosen and swing it around when you need to.

Chris

[NickG]

Nice 1 Chris! Be sure to write it up in another thread! 

[Darren]

Or just write it up here you like, makes it easier for peeps to find all the different ways of tackling the same subject in one place...

Just a thought, your call of course 

[bogstandard]

I think you will find that there is a reason for having two lock on faces for a modern toolpost.

As previously mentioned, the dovetails are usually 60 degree, that is to give more surface area for clamping and so aid rigidity.

Now to the two sides.

Having a single sided holder and swinging it about is harking back to the days of lantern toolposts and HSS or carbon ground up tooling. This is where the tool tip is swung about until the angles and height look correct and the tool is used like that.

The modern way of tooling use is the tipped variety, and they really do rely on being set at the correct angle to the job for them to cut efficiently. Thousands of design hours have gone into doing just that. So the toolpost is set to 90 degs for one face and  parallel to the workpiece on the other, then locked up solid. I find that using this criteria for ground tooling works just as well, and only requires the toolpost moving on very rare occasions, just to give me a bit of deep cutting clearance.

Look at almost any good tipped tooling set, and you will see they have shaped holders. When those are mounted into a squared toolpost, the tips of the tool are at the correct cutting angles to the job, and should be left that way.

Bogs

[NickG]

Good point John, I always use HSS and am always swinging the tool post about. Even a 4 way post is far better than the single one I have - it's awful!

[raynerd]

Hi John, that is interesting and makes sense to me. I`m forever swinging the tool post around to gain a better cutting angle for my HSS tools. I think perhaps much of it is lack of experience but I can certainly see when I have it set at a better angle, just trial and error and I see it cuts better. I`ve not got any indexable or "expensive" tooling but can see how these are set to the correct angle to be mounted in one of the faces of a two face QCTP with the post set square to the work.

I guess after reading that, for now I`m going to have to continue to swing the tooling around as I don`t know how to mount or grind my tooling correctly so as to set it up in a modern two face QCTP. I suppose there will be little benefit of having two faces as I have already admitted that I will probably have to continue to swing it occasionally anyway, so I guess swinging it horizontal to the work is little extra effort. That being said a single faced QCTP will still be much quicker and more effecient so this project is still all go....

Darren - if you don`t mind me posting here then I will do! I`ll get some picks up tonight -   

Chris

[Brass_Machine]

Don't know how I missed this. Looks good Darren. You did a fantastic job!

Eric

[Darren]

Wow Eric, where you been 

Thanks for the comments, the fact that I'm still using it and it's the only tool post used on my main lathe must mean it worked 

In fact I was lathing something up earlier this evening....

[John Hill]

Hom hum, I guess I am on the outer again!   I use the original four-way thing the lathe came with and I use a collection of different sized tools that have came my way through various routes which I fear may not fit well into a QCTP?

Of course changing tools can be a pain as almost all of them need packing in one way or another but I have almost learned which packers are used with each tool.

[Darren]

It no bad thing John, I still feel the standard four way post gives a more solid hold on tooling than either of my two QCTP's.

[NickG]

The problem for me with the HSS is, it's ok finding packing but depending on where you put it, and how much you tighten the screws up varies the height. Also, when regrinding the tools it changes the height. A QCTP would make things so much quicker for me.

For the home workshop I still need the versatility of being able to swing the toolpost around. Maybe for CNC's and things they can be set rigidly parallel and normal to the spindle axis and let the tipped / indexible tooling holders deal with the angles.

Nick

[bogstandard]

Nick,

If you are going to be predominantly using HSS, you should really be looking at a lantern type toolholder.

http://cgi.ebay.com/ATLAS-CRAFTSMAN-10-12-LATHE-LANTERN-TOOL-POST-&-WRENCH_W0QQitemZ280394302671QQcmdZViewItemQQimsxZ20090907?IMSfp=TL090907187002r5035

They are very old technology, but just by loosening one top screw, the tip of the tool can be swung into almost any position within seconds.

Not as rigid as a normal toolpost, but very fast to use.

Bogs

[NickG]

Bogs, I did  consider those but to get the centre height you're changing the rake angle. Suppose you just grind the tools to account for that though?

[bogstandard]

You're right Nick.

You will find that when using one of these, you give your tooling a couple of extra degrees all round, just to make up for it. Or else, put a bit of packing underneath, but that isn't as critical as trying to shim for correct height, just a matter of raising the tool a bit.

Bogs

[John Stevenson]

Here's one I did originally in the 1980's

http://www.metalwebnews.com/howto/toolpost/toolpost.html

This was done because at that time there were no cheap imports and the only one available was the Myford Dickinson one which was too expensive for me at the time.

It wasn't a copy of anything and a clean sheet design, compared to modern posts the dovetails are inverted. This was done purposely as I wanted the holders to be easy to make going along the lines of you need more holders than posts.

The holders were made in strips on a horizontal mill with a 60 degree angles cutter at night school in 18" lengths and cut off as needed.
That particular post and the 17 ? odd holders have long gone but I still use a slightly scaled up version on my lathes today.
I have three nearly identical posts and about 50 holders what swap between 3 lathes.

Would I do the same today ?
Probably not as it's cheaper to buy these items but sometimes it's not about buying / obtaining. most of my early equipment like rotary tables, dividing heads, morse taper arbors and even a Dore Westbury milling machine were made in my workshop.
The experience of doing this is priceless.

John S.

[NickG]

Good stuff John S, the type I want is circa £100 so if I could make one for nothing it would be good, however, it'd be a pretty sizeable project for me and the limited time I get in the workshop.

I used to have a dore-westbury but unfortunately it wasn't a particularly well made example. When I was younger, I also bought a Centec 2A mill (great quality machine), I intended to fit the vertical head from my dore-westbury onto it but as it wasn't too clever it wasn't worth it so bought a new mill. I got the milling machine from an auction, but bizzarely, it belonged to an, unfortunately, deceased member of our club. He had a dore-westbury vertical head ready converted but donated that to the club. I offered the club good money for it as it was a good one, but they declined saying it was useful to train people up on rather than the big beast of a warco thing!

Nick

[raynerd]

Well guys - it is a start! I`ve hacked a piece off the end of my steel bar and all is looking good. The chop saw went through it pretty easily, took about 3 minutes to get to half way at which point I let it cool for 30 minutes then went back to finish it off. Clean cut just not perfectly straight but I soon rectified that by facing the end up roughly in the lathe. However, not using the chop saw before, I cut about 0.25" over size to give me some play and basically I have this on the block so I`m going to have to take it off in the lathe - that could take a while! So next job is to face up the end and bring to size and then drill the bore for the off centre cam. I just need to have a think about sizes and also whether I need to drill it off centre like Darren did. I`m not to sure that if I just drill it centre that I`ll have enough clearence anyway. I guess I need to face up and then have a good mark out and think....

Anyway, tiz a start!



First picture shows the bar and also the block that I intially found and was going to use. I choose the bar in the end because the block didn`t give me enough height.

[Darren]

Beats handsawing dunit.....did the saw complain or the blade grab at all? It looks like it cut fairly well without too much burning evidence......nice one 

I suspect that is not hardened steel which you will be o-so-grateful for.....

[NickG]

Good stuff Chris, I will be watching and hopefully learning as my 1 way tool post is annoying me so much I'm very tempted to make this my next project now!

[raynerd]

Got a little more done today and all thanks to my new 2 1/2 end mill cutter! Cuts the stuff like butter and with a 90deg side, it also allowed me to do up to a square side ready for the dovetails:





I have put a first drill down it but couldn`t go further since I need a 5/8" drill. Since it being perfectly central is not critical, I`ll be able to set this back up on the lathe for the centre drill and bore.

Anyway - massive problems now since I purchased a 45deg dovetail cutter but it doesn`t seem to want to cut for me! It just screams. I`ve tried changing the speeds and nothing. It is making a cut but really really slowly and a terrible sound. Any adivce?

Chris

[Darren]

Anyway - massive problems now since I purchased a 45deg dovetail cutter but it doesn`t seem to want to cut for me! It just screams. I`ve tried changing the speeds and nothing. It is making a cut but really really slowly and a terrible sound. Any adivce?

Chris

Use your shaper........


Sorry, couldn't resist.....but shapers do make dovetails rather easily.

Never used a dovetail cutter on the mill, but it sounds like you might be tickling it at too high a speed? I'm just guessing, wait for someone who might actually know something to come along.....

You need to remove as much material as you can before using the dovetail cutter, I can tell you that much.

[bogstandard]

A dovetail cutter is a very fragile toobit. By the sounds of it, you have already done it fatal damage.

You need very fine feeds and lots of coolant and lube.

I made a new topslide for a lathe last year out of gauge plate, which I am sure is just as tough as the stuff you are using, but because of the way the cutter was treated, it is still as good as brand new, and will be used again when I make some tooling for my lathe.

Sounds like a very expensive mistake to me.

You can use a flycutter to make external dovetails fairly easily, but you need to be able to grind the tool accurately. In fact, when I come to cut mine, I will most probably use a flycutter for most of the rough metal removal, and save the precious dovetail cutter for final finishing.

Bogs

[raynerd]

Humm, thanks for the reply John. That is good idea, so basically grind up some HSS perhaps just short of 45deg and use that as a single point cutting tool in the flycutter. Then use the dovetail to finish the job after the bulk of the material has been removed by the flycutter.
I could possibly have damaged my dovetail cutter but it seems fine enough, still as sharp as before and no noticable damage. I didn`t use it for very long, only a minute before I realised I was rushing and decided to leave while I found some more info. Will have to see if I have spoilt it but I guess not....

I`ll give the flycutter method a go and I guess the cutter shape would be just less than 45deg to allow the finish to be put on with the dovetail cutter.

Thanks for the suggestion. I`ll let you know how I get on tomorrow.

Darren - I really wanted to use my shaper for the dovetails but I`m still having issues. I`ve smashed a piece of the pully trying to remove it from the shaft - it has all siezed up and I think I hit it a bit hard  .  Now I need to drill a hole for some brackets and then mount it but it is getting around to doing it. If I`m being honest, it is the only bit of kit that isn`t here at my house, it is at my grandparents as I don`t have any room for it here (it won`t fit in the cellar), consequently I don`t get much time to work on it, or at least I have to make more of an effort. I hope to have it running in the next few weeks, although I said that a month ago!

Chris

[NickG]

Chris,

Even if the flycutter works for the tool post, will you be able to get in to do the holders with the fly cutter?

Nick

[raynerd]

Tiz a good point Nick. I`ve just seen Stews post on his gauge he is making and he used a boring bar style tool in effect to fly cut the material out.

If you look back to the original post that Darren got his inspiration from, after taking out the main channel with a end mill he then took the entire dovetail cut with the dovetail cutter. I appreciate they are delicate but I have seen them used progressively to take the entire cut. No doubt if you removed some of the material first with a profiled fly cutter they would save the life of the dovetail cutter but I`m sure it should be able to do the entire cut. Think I need to use more coolant and a slower feed..... 

[raynerd]

...also reading the other thread on QCTP`s and I wish I`d read Darrens advice earlier regarding doing the dovetails first - If I mess these up then the whole thing is scrapped and I`ve since spent much more time boring out the centre    

[NickG]

It'll be ok, just take a step back and be patient. The amount of parts I ruin because I get over confident and take bigger cuts to hurry things up ... I'm getting better though.

Nick

[DICKEYBIRD]

I envy you fellows with shapers.  Not having one, I made a dovetail cutter with a carbide insert and it works pretty well.  You still have to go fairly slow but we have lots of time in the home shop, right?

It's made from (what we call over here in the states) 4140 pre-hard.

[Darren]

I had considered making one of those tools, what are you cutting...alloy?

How is it with steel?

[DICKEYBIRD]

Yup, that was 2024 aluminum in the pic but it cuts steel & cast pretty well too.  Just as in other cutting tools, you have to back down the speed & depth of cut appropriately.

One of these days when I have my audience with the Wizard of Oz and get a brain, I'll actually learn how to compute SFM properly and know I have it right.

[NickG]

Looks fantastic that cutter. 

[Darren]

Good to know it works......

Thanks for posting, gives me more reason to make one now...

[DICKEYBIRD]

I finally remembered the website where the inspiration to build my dovetail cutter came from: http://www.gadgetbuilder.com/ToolHolders.html  John Moran's a clever fellow and makes neat tools from whatever he's able to find lying around.

Another example here: http://www.cnccookbook.com/MTMillDovetail.htm

[NickG]

Some clever stuff on that first website!

[crazypj]

This just turned up on Homemadetools.net
Didn't realise it was made 2009
Anyway, the original material looks like a bucket pin from a large excavator.