Lever collet closer loosening

bogie · Aug 5, 2017

Machine is a 1965 10L Heavy 10, which came to me without a collet closer. I've been using a handwheel collet closer.

I inherited a spindle and lever collet closer. Tried to do a transplant on the spindle, and it seems just a week little smidge too large, so I put stuff back the way it was with the original spindle. I've made a spacer to lengthen the "snoot" at the "rear" of the spindle to accept the collet closer.

It works fine, until I try to do production, at which point it loosens.

Any hints?

I'll check back to this, and you can also find me at the Facebook "Bridgeport User Group."

Thanks a bunch!

Chuck Bogardus
St. Louis

bogie · Aug 5, 2017

Okay, I may have kludged a solution... Tell me if I'm stupid, okay?

I remembered how the collet closer on a lathe I used to use would lock down with a sort of swiveling key. Okay, this doesn't have that. Did some searching and someone said that their collet closer went in the spindle darn near as a press fit. Okay - My adapter is larger than that (1.750ish). So, I drilled and tapped a half-dozen 1/4-28 set screw holes - the adapter is now firmly affixed to the "back" of the tailstock, and to the "second" shaft (not the inside, where it steps down...) of the collet closer.

I set the collet closer, tightened the set screws, and it repeated for a half-dozen parts. So maybe I've fixed it.

FWIW, the previous owner of this collet closer (and the spindle it came with) was such a supergenius that he filled the spindle interior and the collet closer interior with a heavy black grease. Time to play with some brake clean, rags and shoestrings...

Please, if it looks like I'm getting into trouble with my kludge fix, let me know?

TDegenhart · Aug 5, 2017

bogie said:
Okay, I may have kludged a solution... Tell me if I'm stupid, okay?

I remembered how the collet closer on a lathe I used to use would lock down with a sort of swiveling key. Okay, this doesn't have that. Did some searching and someone said that their collet closer went in the spindle darn near as a press fit. Okay - My adapter is larger than that (1.750ish). So, I drilled and tapped a half-dozen 1/4-28 set screw holes - the adapter is now firmly affixed to the "back" of the tailstock(headstock?), and to the "second" shaft (not the inside, where it steps down...) of the collet closer.

I set the collet closer, tightened the set screws, and it repeated for a half-dozen parts. So maybe I've fixed it.

FWIW, the previous owner of this collet closer (and the spindle it came with) was such a supergenius that he filled the spindle interior and the collet closer interior with a heavy black grease. Time to play with some brake clean, rags and shoestrings...

Please, if it looks like I'm getting into trouble with my kludge fix, let me know?

Are you referring to the collet loosening during part changing with the spindle turning?

Some lathes like the Hardinge have a key lock that prevented that loosening or tightening of the collet so that parts can be put in or taken out of the collet with the spindle turning. That I know of, the SB lever closer does not have that. On my heavy 10 I have to stop the the spindle, operate the collet closer, then start the machine to maintain constant collet pressure.

Tom

jim rozen · Aug 5, 2017

If your lever close is actually south bend (not for example, royal or some other brand) this is probably what is going on:

Most owners of lathes like that don't use them for production. So they remove a small diameter, long dowel pin that
presses into the leftmost knurled handle. It's actually shown on the SB parts breakdown. The pin slides into
what looks like a small keyway in the knurled knob alongside the far left one.

Without that dowel pin, the collet will unwind a bit every time you stop the machine. Gets looser and looser as parts
are run. Most no-production folks want to be able to change collets rapidly so they yank the pin out.

If you re-install that dowel pin, then you will need to get an allen wrench into the hole on the other (to the right of the
leftmost knurled knob) collet knob to slack the setscrew, so you can then adjust the collet closer tension. Once you have it
spot on, tighten the setscrew again. If that dowel pin is in place, it will keep its setting.

TDegenhart · Aug 5, 2017

The closer on my heavy 10 does not have the pin, nor does it have provisions for a pin. The pin must have been a design improvement.

Tom

jim rozen · Aug 6, 2017

TDegenhart said:
The closer on my heavy 10 does not have the pin, nor does it have provisions for a pin. The pin must have been a design improvement.

Tom

Look close. Often the pin is sheared off flush with the knob surface, deliberately. The feature is called out clearly in the original
SB parts book breakdown.

jim rozen · Aug 6, 2017

jim rozen said:
Look close. Often the pin is sheared off flush with the knob surface, deliberately. The feature is called out clearly in the original
SB parts book breakdown.

The pin is actually pressed into the closer body, not the leftmost knob, sorry for the confusion - the right hand knob has the slot
in it to accept the pin, which is part 32 in the diagram. Setscrew 11 has to be slacked to allow adjustment.

TDegenhart · Aug 6, 2017

I looked carefully for evidences of a pin/hole. There are none. I suspect that the pin was a feature that was added after the unit I have was made. Further, part 11, a set screw is a dog point and goes into a recess in the drawbar tube, part 18.

Perhaps SBLatheMan could comment>

Tom

SBLatheman · Aug 6, 2017

TDegenhart said:
I looked carefully for evidences of a pin/hole. There are none. I suspect that the pin was a feature that was added after the unit I have was made. Further, part 11, a set screw is a dog point and goes into a recess in the drawbar tube, part 18.

Perhaps SBLatheMan could comment>

Tom

The design prior to the one Jim shows did not have the locking feature. There was a set screw, spring and shoe that provided friction, but not designed to shift on the fly.
http://www.wswells.com/data/parts/924D.pdf

Ted

two-can · Dec 20, 2017

SBLatheman said:
The design prior to the one Jim shows did not have the locking feature. There was a set screw, spring and shoe that provided friction, but not designed to shift on the fly.
http://www.wswells.com/data/parts/924D.pdf

Ted

Is there a parts call out for the Model 9A lathe as well?

SBLatheman · Dec 20, 2017

two-can said:
Is there a parts call out for the Model 9A lathe as well?

Yours should be one of these:
http://www.wswells.com/data/parts/907J.pdf
Ted

RF · Dec 20, 2017

Ted,

Will these collet closers fit a 9"JR or did they have their own style?

Rocco

SBLatheman · Dec 20, 2017

RF said:
Ted,

Will these collet closers fit a 9"JR or did they have their own style?

Rocco

I don't know for sure. The Junior had its own before the Workshop lathe was invented, but you might be able to make it fit.
Ted

two-can · Dec 21, 2017

SBLatheman said:
Yours should be one of these:
http://www.wswells.com/data/parts/907J.pdf
Ted

Thanks, Ted.

RF · Dec 21, 2017

SBLatheman said:
I don't know for sure. The Junior had its own before the Workshop lathe was invented, but you might be able to make it fit.
Ted

OK, Thanks Ted

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