How does a collet closer work?

Call Hardinge!

GWE

I have never examined one from Hardinge, but I will try to describe how the one on my 12x24" Clausing works.

1) The main tube reaches through to screw onto the back of the collet. 2) It has a cap which fits around a flange on the end of the spindle. This cap has a series of notches in it, which engage a tiltable key. You tilt the key out of engagement to screw the drawbar onto the back of the collet, or to adjust the amount of take-up needed.

This cap rests against the flange.

3) The cap has another cavity facing away from the headstock in which the three L-shaped levers live. The levers protrude partially through the cavity floor, to press against the spindle flange. As the ends of the L-shaped levers are pressed outwards from the center of the shaft, they press upon the flange, drawing the drawbar out a little.

Note that it only draws a little, so the drawtube has to be screwed onto the collet just the right amount -- and may have to be adjusted if the diameter of the workpiece varies.

4) Attached to the headstock is a support to which is attached a hand lever. This lever carries a bearing in a gimbal. The inner race of the bearing contains a cylindrical projection which fits inside the ends of the three L-shaped levers. The part of the cylindrical projection closer to the bearing is turned to a smaller diameter than the part closer to the headstock. 5) When the hand lever is towards the headstock, the rounded ends of the L-shaped levers drop into the reduced diameter of the projection.

When the hand lever is away from the headstock, the rounded ends of the L-shaped levers ride up to the larger diameter. This pushes on the spindle flange, thus drawing the drawtube out and closing the collets.

6) The bearing in the hand lever's gimbals allows the rest of the closer assembly to rotate with the spindle, while the hand lever does not rotate.

Is it possible that you are missing the hand lever and its bearing and cylindrical projection?

Or -- is it possible that you are not pushing the lever far enough towards the headstock to allow the rounded ends of the levers to drop into the reduced diameter section?

While I've been typing this, a script has been building a skeleton web page from some photos which I just shot. Now to go flesh out the skeleton with some text.

Nope -- it is not yet done. The URL will be (when it is done:

O.K. Done. So you can go there to see some photos to go with my description here.

I hope that this helps, DoN.

Or Royal, who probably made the closer. They've been helpful and friendly to me in the past.

Mike

These things involve spacer components and such that are easily misplaced.

Ken..how are you trying to adjust the collet closer?

If you can supply a photo of the closer, I may be able to supply any missing parts. Ive some collet closers and parts for DV 59s, as well as other accessories, such as cross slides etc. May I assume you have the turret version?

Gunner, who specializes in Hardinge lathes of all types through the AHCs

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

I could take mine apart if he needs a run-through.

Gunner, do you by any chance have a lead on a *small* slide for a shaublin 70 lathe? I'd like to fit something like that to a 7" machine.

Jim

"levers protrude partially through the cavity floor, to press against the spindle flange. "

This is the problem I'm pretty sure after staring at it for an hour and taking it apart over and over. I started thinking. Funny how that seems to help sometimes. The levers arn't touching the flange because the flange is too forward for this closer. I suspect when they sold us the machine they gave us one that didn't fit. I borrowed one from another shop and it also didn't work. The tube seems to be just a bit too long or the flange is too far forward. Thanks everybody for taking the time for my latest problem Ken

The quick-and-dirty fix (if the drawtube is not too much too long) would be to make a washer to go inside the cavity to space it just enough out to give you a reasonable adjustment range on the collet. (I would suggest that at the proper size, the collet should be in about 2/3 of its threads, to give adjustment range and strength. This should be no larger than the diameter between two opposite notch bottoms.

I would probably make one a little too thick, of 4140, and then harden it and surface grind it to the right thickness.

A second (and better) solution would be to make a replacement flange which is enough longer than the original so the collet tightens. (you could determine the required length by trying the spacer above.) I would make the flange out of a good hardenable steel (say 4140), and harden and temper it so the notches won't wear with time, and eventually have enough of a slope to disengage the tilting key.

Another better solution would be to turn off some length from the end of the drawtube, but this might mean that you would have to extend the bore and the threads at the end. And, I'm not sure how easy it would be to separate the drawtube from the rest of the mechanism to allow it to be chucked and turned.

I had to do the reverse when I switched from a 2-1/4x8 threaded spindle nose to an L-00 spindle nose. I had to make an extender for the threads, to move them about an extra inch. At least, that was plenty of length so the internal threads did not risk running into the external threads which mated with the original. I used a 6-jaw chuck to minimize chucking distortion of the extension while I was boring and threading it.

Once you have made an extension (not you in this case for your problem), degrease the threads and Loctite the extension in place, so you don't wind up with the extension trapping a collet in the nose adaptor. *That* is a pain to get clear. :-)

You're welcome.

Enjoy, DoN.

Sorry Jim, I sold all the Shaublin stuff I had a couple years ago. If you are willing to use something that "will work", I might be able to find you something. Such are rather easy to make..as the reverse dovetail of the ways is easy to match.

Gunner

"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

If the draw tube is the correct length..slide it all the way in to the closer "nut" and reach into the spindle nose with your finger. There should be approx 1/8'-3/16" gap between the inside of the spindle nose recess and the start of the draw tube.

I really wish you had a camera. There is a trick to putting the fingers back in the right postion if the collet closer has been removed and the fingers pulled out of position

Gunner

"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

"There should be approx 1/8'-3/16" gap" There is no gap and I the 2nd closer I borrowed is even worse. I'm wondering now how to get that flange off and thinking maybe I could make a spacer to go behind it. This is about the only solution we can do with the equipment available. "I really wish you had a camera." We now have a camera and it should be able to put something on web. What do you want to see? I e-mailed you about those accessories to our Hardinge and didn't get a reply. We are interested in a cross slide and 3 and 4 jaw chucks. Ken

OK I took a good look at my hardinge closers this weekend.

Basically the sliding mechanism is more or less cone-shaped, and there are three fingers which bear on the cone.

The fingers are "L" shaped and pivot on the body of the closer. The short arm of the Ls are visible inside the right hand side of the closer body as three small tabs which extend outwards from the body of the closer slightly as the sliding mechanism is shifted to the left.

Those three tabs bear on the flat surface of the detent wheel that is on the end of the drawbar tube - the detents that accept the single latch to hold the collet setting.

So the idea is the lever is shifted to the left, and the profile of the cone-shaped part extends the tabs out to apply draw force to the drawbar. The cone's profile is flat at the final region, so it will hold a tension setting there.

The draw force on the bar tightens the collet into the spindle nose and retains the part.

Which part is not working correctly?

1) does the sliding mechanism not slide? 2) do the tabs not extend outwards to tension the drawbar? 3) is the drawbar simply too long to allow the collet to thread in all the way and tension up?

There's not that much to go wrong, there should be a setting on the rotary handwheel that gives the correct 'snap' as the fingers go overcenter on the cone.

Jim

email me pictures of the collet closer body, the nut at the back of the spindle, a closeup of them together if you can..etc.

I havent seen any emails about Hardinge parts recently. Ive got an aggressive spam killer so it may have spooged your email.

try my snipped-for-privacy@gmail.com email addy..drop ping on the group and Ill go check it. Its not something I check everyday, only use it for things like this. 2gig mailbox for free is good

Gunner

"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

"Which part is not working correctly?

1) does the sliding mechanism not slide? 2) do the tabs not extend outwards to tension the drawbar? 3) is the drawbar simply too long to allow the collet to thread in all the way and tension up? There's not that much to go wrong, there should be a setting on the rotary handwheel that gives the correct 'snap' as the fingers go overcenter on the cone

It appears that the drawbar is too long and that means that when the collets are threaded they can not be drawn up since the tabs are not close enought to engage the flange because the drawbar is bottoming out.

On mine, it is bored to slide over the lathe spindle, and is then held with setscrews. a spacer there is probably not practical.

The options which I see (and suggested in the middle of my longer reply earlier) are:

1) Make a new flange which is longer. (Probably require heat treating capability.

or

2) Make a spacer washer to go around the drawbar tube to live between the lever arms and the flange. You probably want to make this out of a good steel, and to harden and surface grind it -- but you could make up a quick-and-dirty one to try with just mild steel, and turning.

3) Shorten the drawbar -- which requires a way to de-attach it from the rest of the mechanism while you mount it in a chuck to part off the excess length, and (probably) bore the ID a little deeper and pick up the existing thread to extend it.

You have a lathe, obviously. It proably has a 3-jaw or 4-jaw chuck. With those, option 2 should be possible at a minimum. It will get you in service, though every time you remove the drawbar assembly you will have to be careful to not lose the spacer.

Good Luck, DoN.

So it sounds like if you inked the collet threads, you would see that the drawbar female threads are completely engaged - that the end of drawbar is hitting the thread relief edge on the collet.

If this is the correct collet setup for this lathe, what happened that 'stretched' the drawbar? Or is this a retrofit, or a closer off of a different machine?

One way to make this work would be to face off the end of the drawbar, and cut the threads deeper in it. It's a bit tough picking up fine ID threads like that, but it can be done.

Jim

1) Make a new flange which is longer. (Probably require heat treating capability. or

2) Make a spacer washer to go around the drawbar tube to live between the lever arms and the flange. You probably want to make this out of a good steel, and to harden and surface grind it -- but you could make up a quick-and-dirty one to try with just mild steel, and turning.

3) Shorten the drawbar -- which requires a way to de-attach it from the rest of the mechanism while you mount it in a chuck to

part off the excess length, and (probably) bore the ID a little

deeper and pick up the existing thread to extend it. "

I'm going to either make this longer flange or a spacer if possible. I only have a little toy Sears lathe, and toy mill but do have a heat treating furnace. We are trying to get this place up to WW2 standards and right now its very hard to get anything done. Right now I'm busy trying to get out new 1910 Horizontal mill going and fix the buggered threads on our new Ebay grinder. Ken

"email me pictures of the collet closer body, the nut at the back of the spindle, a closeup of them together if you can..etc. " I e-mailed about that cross slide but no answere. My e-mail is snipped-for-privacy@yahoo.com I took pictures and when we were trying to e-mail them it wouldn't work and somehow screwed up the computer. Boss was waiting for me in the parking lot this morning just a bit upset. He told me to fix it even if it took all day. He's had one to many all day sessions fixing the thing. I won't be trying to send any more pictures. Ken