Author Topic: Locking up my cross slide  (Read 19628 times)

bogstandard

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Locking up my cross slide
« on: March 26, 2009, 06:30:02 PM »
I am really digging deep to come up with quickie projects, so this time, it is another on modifying my lathe, the technique used can be used in other projects as well.

Although I only purchased my lathe last year, it is an upgraded version of a fairly old well proven design. That was one of the reasons I chose it, any major problems were sorted out years ago. My problem is that mine is the first reincarnation with the DRO's fitted. I have recently found out an even newer version is available where they have swapped the front on the apron around, swapping over the half nuts selector handle and the saddle feed wheel over, to the civilised position, where you don't get your hand covered in blisters while feeding towards the chuck, burnt by flying red hot swarf. It seems though that they haven't put right the problem I am about to solve.

The problem being, when they fit the read head to the cross slide, it covers over the grub screw that is used to lock the cross slide. This is a real necessity if you are cutting heavily or doing final finishes. The head could be moved to the other side, but under certain conditions, you would lose over 1" of travel towards the chuck, and also the head could be liable to damage from the turning chuck.

So this post will be done in two parts. The first showing what I will be doing, the second actually doing the job. An afternoon should easily see this job done.


So here is my proposal.
The top bit shows how the normal lock works. Tighten up the grub screw, and it pushes the gib against the inner dovetails, that action effectively locks everything up.
That method cannot be used on the other side, as there is no gib strip to protect the precision face of the dovetail.
The solution is shown in the bottom sketch. An angle machined on the end of a bronze piston will be the bit that contacts the dovetail. The other shown bits will be explained as I do it.




It just fell apart in me 'ands boss.

It was honestly that quick, a few minutes and the bit I was after was free of the machine




While I have parts like this off a machine, I always take the opprtunity to look at the bits that will finally wear out. If it is a complicated bit, I would measure and draw it up, and most probably make a spare some time in the future. This time, it isn't needed. I know I could knock one of these out in a couple of hours from a lump of bronze, so no need to carry spares. It also has basic backlash adjustment on it, so it could be adjusted and used while I make a new one.




If I did a cross section of the casting, this is what it would look like.




Also from the end.




I did a rough transfer of the normal locking screw position onto the other side on the casting. This position should be in the right place if the manufacturers have done their maths.




Having blued up, I transferred the line from the bottom to the side face, I now had my first position line.
The blued arrow is showing the position on the top face of the  ball oilers. I don't want to remove them because they might be damaged. I must position the job in the vice so that they are outside of the jaws, otherwise they will get crushed and destroyed.




The dovetail on the machine was measured for height.
After a bit of mental working out, calculating with the diameter of the thru hole, I came to the conclusion that 6mm from the bottom would be an ideal position to drill the hole.




That dimension was duly drawn onto the upright line from previous times. The crossing point was was given a pop mark




Why didn't I just mark it up at half way, at 5mm? There is plenty of meat above the hole, but not a lot below. So to retain maximum integrity, I gave it an extra 1mm of meat below the bottom of the hole.




Because I don't want anything protruding from the finished hole, I need to know how deep to tap it without removing lengthways support to the bronze piston. I had a choice of three different lengths, and have decided to go with the shorter one. The maximum operating range of the grub screw will be less than 1/2 turn, and hopefully massive forces won't be required to lock up the slide, so a 6mm long one should be perfectly OK in this situation.
Because the piston hole will be the same as the tapping size for the grub screw, if it feels a little fragile, I can easily tap a bit deeper and shorten the piston.




So that's it, any questions before I start drilling?


Bogs


Offline Darren

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Re: Locking up my cross slide
« Reply #1 on: March 26, 2009, 07:41:00 PM »
Quick Q

Are you planning to put just the one on the non gib side because your DRO is in the way on the gib side, wasn't too clear in your post.  :scratch:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

bogstandard

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Re: Locking up my cross slide
« Reply #2 on: March 26, 2009, 07:52:15 PM »
That's correct Darren, because of the manufacturers mounting the read head on the locking side, I can't lock my slide up as it is. The locking grub screw is covered over by the read head.

After tomorrow, the problem should be solved.

John

Offline Darren

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Re: Locking up my cross slide
« Reply #3 on: March 26, 2009, 07:58:13 PM »
Gotcha  :thumbup:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline Stilldrillin

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Re: Locking up my cross slide
« Reply #4 on: March 27, 2009, 03:21:22 AM »
               So that's it, any questions before I start drilling?

Bogs

No questions.......

Just watching, quietly......  :thumbup:

When tightening the toolpost, I hand pushed the tool into the rotating chuck jaws the other day!   :scratch:
Soo... I started making my mini lathe carriage lock yesterday!  :wave:

David.
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline John Hill

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Re: Locking up my cross slide
« Reply #5 on: March 27, 2009, 04:01:49 AM »
John, can I just wind the cross slide off the back of the carriage, or do I need to move the splash shield?  I am seriously thinking of trying to get my DRO cable under the slide, where I have it at the moment it blocks my slide lock screw too (mainly because I used the threaded hole to anchor the cable!  ((didnt want to drill holes in the new lathe just yet!)))

BTW, my lathe is presumably much older than yours having stood in the showroom for several years and my saddle feed wheel is on the right hand side too,  my 'manual' shows both saddle types.
From the den of The Artful Bodger

bogstandard

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Re: Locking up my cross slide
« Reply #6 on: March 27, 2009, 05:06:10 AM »
John,

It looked like I had wound the slide off the end, but I took the easy way out.

I slipped the tapered gib strip out, undid the screw on the top holding the leadscrew nut in position, then with a lead hammer gently tapped down on the loose screw on top to release the nut from the slide, and then lifted the slide off the dovetails.

It looked to me as though the backsplash would need to be removed to get enough clearance to wind it off. But I will check later to verify for you.
There is also a screw and floppy washer in the end of the leadscrew that has to be removed. This is to prevent you winding off all the way accidentally.

John

bogstandard

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Re: Locking up my cross slide
« Reply #7 on: March 27, 2009, 07:06:45 AM »
John,

Yes, you can wind the slide all the way off, but you will have to remove the gib strip plus the screw/floppy washer before it will come all the way off.

John

Offline jemglen

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Re: Locking up my cross slide
« Reply #8 on: March 27, 2009, 01:39:32 PM »
So enjoy reading your project and tinkering posts John and learn a lot too.  :clap:

Thank you  :thumbup:

Jerry

bogstandard

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Re: Locking up my cross slide
« Reply #9 on: March 27, 2009, 03:08:27 PM »
Jerry,

I love that word, tinkering.

It really does sum things up at times, poking around the shop looking for little things to put right. I must use it more often.

John

Offline shoey51

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Re: Locking up my cross slide
« Reply #10 on: March 27, 2009, 04:31:15 PM »
So enjoy reading your project and tinkering posts John and learn a lot too.  :clap:

Thank you  :thumbup:

Jerry

I agree :headbang: :clap:

bogstandard

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Re: Locking up my cross slide
« Reply #11 on: March 27, 2009, 08:24:14 PM »
Now to get this post finished, so I can get back to tinkering in the shop.

I spent hours in crisis, wondering if I had made the right decision, so just to play safe, I have decided to go with a slightly longer 8mm grub screw.




The slide was mounted into the mill vice, taking care to keep the oilers out of the way. I doesn't need a super rigid setup, as I am only drilling a fairly small hole. So using a 3-2-1 block to bridge the U shape of the slide, the top face was clamped against the fixed jaw, and the side face seated nicely in the bottom of the jaws.
Near enough is good enough for this bit, so the centre was eyeballed over the pop mark, and once in position, a centre point was drilled.




It was then followed down with a growing range of drills, 4, 5, 6, and then the tapping sized one of 6.8mm.
The reason I did this is because the drill will be breaking thru onto a slanted face. By taking it up in stages reduces the risk of the drill being kicked off line as it broke thru on the other end.




This is the tapping drill going thru, a nice feed thru with no kick at the bottom.
This shot also shows the attempt by the manufacturer to gain a little more precision and long life. They have hand scraped the running surfaces, it is not perfect by any means, but at least they are trying.




I hand tapped to a depth of 10mm. I didn't feel it was worth setting up all the gizmos just for one hole.




This shot shows where the hole broke thru on the slanted face, to me, the position looked perfect for the job being done.




While I had it off, I thought I would show you something I did as soon as the machine was commisioned.
I marked up all four points of the compass around the topslide mount. Because the topslide has only a 90 degree scale on it, by switching from one marked point to another, I can position the top slide on a full 360 degrees. This will allow turning tapers, even away from the chuck, when the tailstock normally gets in the way when using a centre. Not used very often, but it is there when needed, and only takes a few minutes to do.




Twenty minutes later, everything was reassembled, adjusted, and ready for action. I need to do some turning to finish this job off.




The new hole in position.




A length of hex ali bronze was turned down to 6.75mm, just slightly smaller than the 6.8mm tapping hole. If you notice, I also reduced the end slightly. This part, over the years will gradually splay out on the end, not a lot, but would cause the slug to jam in the end of the hole nearest the dovetail. Reducing the end will cure that problem.




Just checking for a nice free sliding fit.




I am lucky in that I have a 60 degree dovetail cutter. I am sure it is easy enough to figure out how to cut the angle on the end if you don't have one.




Sorry about the quality of the pic, this was the best one out of the dozen I took. I must be getting knee trembles about the thought of getting the job finished.
Anyway, I cut the angle on the end of the slug (piston).




So with the rod blued up, it was pushed into the hole and by feel located into it's operating position, with the angled end sitting against the dovetail. In fact, when you push on the end, it goes into the correct position by itself. The rod was marked up where it protruded out of the hole.




Now to get the piston to the correct length. I laid the grub screw and ball bearing along the length, with the grub screw starting at the mark I had just made. Then about half the length of the ball and another mark was made. This is the length of the piston in it's final form.




Now a bit about the ball bearing. I am using a 3/16" diameter. I wouldn't go any larger, but you can go smaller, say down to 1/8" (or a metric equivalent in both cases). The ball is there to apply forwards pressure only from the grub screw, if it wasn't there, the grub screw would also put a friction turning force on the piston, maybe stopping it seating correctly on the dovetail.
It just so happens that my centre drill is 3/16" diameter, so it will be fed into the end of the piston until it makes small side walls in the hole. You can just use an ordinary drill if you wanted.
BTW, if possible try not to use a stainless ball, you need one that can be picked up with a magnet.




The piston with the ball loctited in.




The business end of the grub screw. If you are going to use this technique anywhere, you will need either a flat faced or cone end on it (like this one), a pointy end will go a bit funny when you try to tighten it down onto a ball bearing.




The bits all ready to go into the hole.




The piston was given a good dose of grease, pushed into the hole quickly followed by the grub screw.
Now, why the magnetic ball bearing? If you stick a little magnet into the hole, you should be able to pull the piston out, otherwise you will have to remove the cross slide and push it out with a stick.
It takes only 1/4 turn of the grub screw to go from fully slack to fully tight.



Did it work? - Yes

Did it work well? - Yes

Did it lock the cross slide solid? - Yes

Any problems with it? - No

What is the subject of your next topic? - Absolutely no idea

Bogs

Offline DeereGuy

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Re: Locking up my cross slide
« Reply #12 on: March 27, 2009, 08:44:17 PM »
Thanks for the nice write up John, I will give it a shot now, just as soon as I get the rest of the east interior wall done.  Hopefully this weekend then paint next weekend.  I did worry about running the chuck into the head in a moment of distraction.

Bob

Offline shoey51

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Re: Locking up my cross slide
« Reply #13 on: March 27, 2009, 08:46:23 PM »
 :D a happy chappy by all accounts well done :thumbup: :clap:

bogstandard

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Re: Locking up my cross slide
« Reply #14 on: March 27, 2009, 09:13:30 PM »
Bob,

That little distraction would cost you well over 100 bucks. Not a thing you want to do very often.
I will in fact be doing this mod on my topslide as well, because to fit the read head on there, I had to cover up the locking screw, and it can only be accessed for about 50% of the time.

Shoey,

I am always happy when I am in my shop. When I can't get in there, I turn into a nasty, grumpy old phart.


Bogs

Offline Stilldrillin

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Re: Locking up my cross slide
« Reply #15 on: March 28, 2009, 04:29:32 AM »
Thank you John!

Another crackin` write up, full of great ideas & reasons why......  :clap:

David.
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

bogstandard

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Re: Locking up my cross slide
« Reply #16 on: March 28, 2009, 05:40:26 PM »
I'm glad you are learning little bits 'n bobs.

The way I learn is read everything twice and give all piccies a good scanning.

Sometimes people forget to mention little hints and tips they use themselves in their posts, but they are there for all the world to see if you look for them.

A lot of what I show aren't my ideas, but what I have picked up in industry over the last 40 odd years, and utilised for my own benefit. This post consists of two that I have picked up. The ball bearing idea was used in a shaft friction device on a printing machine, and the dovetail pressure pad was a system used on my old Atlas topslide for locking the angle setting.

There is very little new in this world when it comes to mechanical things.

My problem at the moment is finding things to show that are interesting enough.

I did a bit of work today, and took piccies as I went along, but then thought it wasn't worth showing as all it was about, is me doing a bit of rough stuff on an RT, and a touch of filing at the end.

So maybe it is time for me to get an engine on the boil, or finish off one that is nearly there, just to get me back into the swing of things.

Bogs

Offline Darren

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Re: Locking up my cross slide
« Reply #17 on: March 28, 2009, 06:12:18 PM »
John,

Just ramble on, there is usually something we can glean from your, or anybodies posts.

Besides, it's better than Corro ain't it....  :ddb:
(or American Idol or sumut that's on every night at the mo)


Is it just me, but it seems very few people seem to be doing much posting, just a small handful of regulars....don't be shy guys... :thumbup:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

bogstandard

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Re: Locking up my cross slide
« Reply #18 on: March 28, 2009, 07:38:08 PM »
Darren,

I have found that our US cousins do a lot of family stuff at weekends, plus also they are all coming out of hibernation, so tidying up jobs will take priority. In a couple of months, you will find it drops off a lot, as they are on vacation or their workshops are too hot to work in.

We are fairly lucky in that we have a moderate climate, so usually we can get into our shops most times, and we have also learned to ignore the needs of the family.

That reminds me, I haven't seen the wife for a couple of days, no wonder I'm feeling hungry.


Bogs

Offline DeereGuy

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Re: Locking up my cross slide
« Reply #19 on: March 29, 2009, 10:13:27 AM »
It is tough for me to get shop time between May and September due to outdoor work that still needs to be done here at home.  Last year at work we had a project that required 60 to 70 hours a week through September and last Spring I was in the UK for several weeks.  There is a chance I will be going again for another project starting up next month although this one should not be as intense as last years.

John as far as taking pics of things that have been shown before I was in the same delima this morning.  I am cutting up the plates needed for the base, side frame and crankshat support for the Webster I started last winter.  I decided it would be pretty boring to look at so I didn't take any pics.

Offline jemglen

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Re: Locking up my cross slide
« Reply #20 on: March 30, 2009, 03:10:56 AM »
John, once again, thanks for a great write-up, very enjoyable  :)

I believe you could make brewing up a cup of tea look interesting (take the backlash out of the teapot lid, tweak the teabags for maximum flow, adjust the handle on the mug for optimum attack!  :lol:)

Jerry

bogstandard

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Re: Locking up my cross slide
« Reply #21 on: March 30, 2009, 03:57:22 AM »
I certainly would try that Jerry, only trouble is, I don't like the stuff.

I became addicted to coffee about 25 years ago, and haven't had a 'cuppa' since.

Bogs

Offline jemglen

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Re: Locking up my cross slide
« Reply #22 on: March 30, 2009, 05:11:06 AM »
You and me both, I can't stand the stuff, even the smell is enough to turn my stomach.

Trouble is, not liking tea is like not liking football or F1 if you're a bloke... I get some very funny looks  :bugeye:

Jerry

Offline Darren

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Re: Locking up my cross slide
« Reply #23 on: March 30, 2009, 05:30:39 AM »
T is for girls   :)

Real men drink coffee  :ddb: :ddb: :ddb:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline rleete

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Re: Locking up my cross slide
« Reply #24 on: April 27, 2009, 12:02:14 PM »
Is it just me, but it seems very few people seem to be doing much posting, just a small handful of regulars....don't be shy guys... :thumbup:

Not shy, just not much constructive to add.  Don't take the silence as lack of interest (at least on my part), but just being to busy to post much.
Creating scrap, one part at a time

Offline kvom

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Re: Locking up my cross slide
« Reply #25 on: April 27, 2009, 02:17:51 PM »
Neither of the lathes I have worked on seem to need a cross-slide lock.  When I am turning on the Monarch I can see that the Y DRO value never changes.  The same applies on the carriage, although it does have a lock there.  Do you need one since it's a lighter lathe or has more vibration?  It appears that there is a screw on the slide that need to be tightened when using the taper attachment, and it does seem to act as a lock as well.   The other lathe is at school and is a Harrison 14"

Offline Stilldrillin

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Re: Locking up my cross slide
« Reply #26 on: April 28, 2009, 02:03:40 AM »
Is it just me, but it seems very few people seem to be doing much posting, just a small handful of regulars....don't be shy guys... :thumbup:

Not shy, just not much constructive to add.  Don't take the silence as lack of interest (at least on my part), but just being to busy to post much.

Also...... You regulars have already discussed & written everything there is to add....... Before I manage to get here!  ::)

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

bogstandard

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Re: Locking up my cross slide
« Reply #27 on: April 28, 2009, 04:25:30 AM »
There is nothing wrong about doing a posting about the same thing David, usually it is the subtle differences that are the major things.
Everyone has their own little way of doing things.


John


Offline Darren

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Re: Locking up my cross slide
« Reply #28 on: April 28, 2009, 04:32:12 AM »
Yes, and then we can pick out the best bits/comments/ideas that suit our own individual needs/tooling  :thumbup:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline foozer

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Re: Locking up my cross slide
« Reply #29 on: July 17, 2009, 01:34:43 PM »
So that's it, any questions before I start drilling?


Bogs


Just a quickie to show your post are useful. From your idea I did a similar to my own. Really hate drilling holes into the machine for a gizmo that may not work, the outcome and yours shows it is viable. Not enough room to add the little ball bearing and maintain a reasonable amount of thread for the screw but really not an issue. Did it, the screw and little brass bit, works like a champ. For this old metal toy anything that improves rigidity is a blessing.  Dum De Dum

You know my gib screws were pointed things . . .  I use the word "WERE" you know what happened after a few times of locking down the slide.

Robert
« Last Edit: July 17, 2009, 01:36:18 PM by foozer »
Ignorance is Bliss, thus I aim for Perfection

bogstandard

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Re: Locking up my cross slide
« Reply #30 on: July 17, 2009, 01:55:36 PM »
Nice one Robert. I'm glad the technique worked for you.

Bogs