# Craftsman 3 Jaw Chuck Problem....



## Olddaddy (Jun 13, 2016)

I've had my 12" Craftsman for a few months now and have regularly switched the jaws around from inside to outside positions.  I've cleaned it and oiled it and all was well until last weekend.  I took the jaws out to turn them and when I re-installed them the would not turn in and tighten at all.  There are some broken spots on the teeth, but they have always worked before.  I cleaned, checked carefully, oil and tried repeatedly to no avail.  They are in the correct 1,2,3 positions.  The Chuck is marked The Cushman Chuck Company, Hartford, CT. USA and it 5" in diameter.  Can I replace the jaws?  Should I look for another Chuck?  If so, what do you guys recommend?  And I have no idea why the pic is upside down......


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## TOOLMASTER (Jun 13, 2016)

ARe all the screws tight?


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## Olddaddy (Jun 13, 2016)

Yes, all are tight.  The odd thing is nothing I've done and nothing I can see on the Chuck or jaws has changed.....but, they will only function one way, not the other.


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## Uglydog (Jun 13, 2016)

Did you get them in the correct sequence?

Daryl
MN


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## talvare (Jun 13, 2016)

As Daryl has said. Correct sequence is important when re-installing the jaws. Jaw #1 needs to go in first as you rotate the scroll, then #2, etc. Maybe you already know about that, if so, I apologize. Don't want to insult you. Also check that there isn't some swarf in the scroll that could cause the jaws to bind.

Ted


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## Olddaddy (Jun 13, 2016)

I am not insulted at all, I appreciate the help.  I did confirm sequence and carefully cleaned, re-cleaned and checked, but no go.  It is odd as they worked fine before.  Some mystery force perhaps?  I mean, physics is physics right?  Something has to be preventing it, but my eyes don't see it.  I will try again and report back.


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## talvare (Jun 13, 2016)

Any chance you could post another picture of the chuck with a straight on shot from the front of the chuck ?


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## Olddaddy (Jun 13, 2016)

Sure, but it will be tomorrow.  I'm too lazy to get dressed and go back out into the shop tonight.  I'll pull the jaws and get pics of them as well.


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## talvare (Jun 13, 2016)

Good, I'll check back tomorrow. Take one picture before you remove the jaws.


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## chips&more (Jun 13, 2016)

Take it “all” apart, clean it good, check for problems, give it a fresh grease job, put it back together, then get back to us.


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## RJSakowski (Jun 14, 2016)

Incorrect position of the chuck jaws wouldn't cause binding.  The jaws just wouldn't center properly.  I suspect some chips have gotten into the scroll and are causing the binding.  The solution posted by Chips&More should clear the problem.


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## wa5cab (Jun 14, 2016)

A photo of the tooth side of any one or all three of the jaws would reveal the answer.  But unless the Cushman is one of the very very few solid jaw 3-jaw chucks ever made, you cannot reverse the jaws.  The exception would be jaws where the tooth shape is oval instead of the normal arc shape.  Almost all 3-jaw scroll type chucks with solid one-piece jaws originally come with two sets of three jaws.  They look almost the same except that the teeth are reversed relative to the steps.  

If you pull the jaws out and look down through the slot at the scroll, what you will see are a row of curved teeth.  The curvature of the teeth on the jaw must match the curvature of the teeth on the scroll.

This all assumes, of course, that you have a normal chuck.


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## Mondo (Jun 14, 2016)

Olddaddy said:


> I've had my 12" Craftsman for a few months now and have regularly switched the jaws around from inside to outside positions.  I've cleaned it and oiled it and all was well until last weekend.  I took the jaws out to turn them and when I re-installed them the would not turn in and tighten at all.  There are some broken spots on the teeth, but they have always worked before.  I cleaned, checked carefully, oil and tried repeatedly to no avail.  They are in the correct 1,2,3 positions.  The Chuck is marked The Cushman Chuck Company, Hartford, CT. USA and it 5" in diameter.  Can I replace the jaws?  Should I look for another Chuck?  If so, what do you guys recommend?  And I have no idea why the pic is upside down......
> 
> View attachment 130714



I did not know there were any scroll chucks that permitted the jaws be reversed.  The curved "threads" on the inside of the jaws will fit the scroll only one way. Typically you need two sets of jaws, one for inside work and one for outside work.


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## wa5cab (Jun 14, 2016)

I can't recall who made it or when but somewhere within the past two or three years I saw a photo of the teeth on the inner part of the jaws.  Probably worked about as well as the traditional versions so long as you never chucked on the ID of a part.  Given the increased cost of making the teeth, I can't imagine that the manufacturer saved any money by not having to supply two sets of teeth.


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## Olddaddy (Jun 14, 2016)

Here are a couple of pics.  I think the jaws are not meant to reverse, which makes it all the stranger as I have reversed them.....really.  Looking at them tonight they appear to be an arc thread as mentioned here and not reversible.  I feel like I am entering the Twilight Zone!


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## RJSakowski (Jun 14, 2016)

You are correct that the jaws are not reversible.  Reversing them is most likely what caused the damage. You may have considerable damage to the scroll as well as bit of broken teeth.


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## roadie33 (Jun 14, 2016)

I got that same chuck with my 12" Craftsman and it came with 2 sets of jaws.
One set for inside and one set for outside.


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## talvare (Jun 15, 2016)

roadie33 said:


> I got that same chuck with my 12" Craftsman and it came with 2 sets of jaws.
> One set for inside and one set for outside.



Well Olddaddy, I think you'd better start looking through all your drawers and cabinets for that other set of jaws so you can get yourself out of the "Twilight Zone" 
I think Mike R. has your answer.

Ted


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## cdhknives (Jun 15, 2016)

Any chance you crashed the chuck?  Mine did the same thing...after I ran a 1/4" bit to close and stalled the headstock via chuck jaw to toolbit contact!


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## Olddaddy (Jun 15, 2016)

Well,  I see why the wouldn't reverse, but they did.....unless I imagined it.  The teeth were broken when I got the lathe.  I took both chucks apart before using them and cleaned and lubricated them.  I have looked very carefully and do not see other jaws in any of the bits and pieces boxes.  I like the Chuck and would buy more jaws if I knew what to look for.  There are no part numbers or anything on the Chuck or the jaws.  Would I be able to buy by dimension?


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## roadie33 (Jun 15, 2016)

You'd be better off buying a new 3 Jaw like I did.
I use the old one on my wood lathe now.


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## Olddaddy (Jun 15, 2016)

What did you buy?


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## roadie33 (Jun 15, 2016)

It was just a cheap import 3 jaw from eBay. $89 with reversible jaws.
Ordered the backing plate from Little Machine Shop for the 1 1/2 x 8 spindle and drilled and tapped it for the bolts.
Bolted it together then trued up the back plate with chuck on at real low speed.
Back plate is Cast iron so it cuts easy.
So far it has worked great with no problems and it is within .001 to .002.
Good enough for what I do on the lathe.


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## Olddaddy (Jun 16, 2016)

I appreciate all the response and advice/help.  I guess I will muddle along till I find a set of jaws or a replacement Chuck.  Thanks again Gents!


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## timmeh (Jun 17, 2016)

Some swarf jammed in the scroll plate? Had that happen on numerous occasions back in the machining days. Could just be something small stuck there or forced into the scroll thread, causes stiffness/complete stop in the jaws movement. Dismantle chuck, close inspection of inside may be all that's needed. DON'T lube with grease, very light oil if nothing at all, the stickier the lube, the more likely to gather more crap!    Slippery, not sticky. (works fer change gears and the like too)


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