Problem With The Screws On My 4 Jaw Atlas Chuck

M

master53yoda

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I just put the 4 jaw chuck on my 12x36 craftsman commercial lathe for the first time and when I started to adjust it, I found that the square adjusting holes were all rounded out and non adjustable. Has any had this problem, are their any suggestions as to how to resolve it. can the screw plugs be removed so the screws can be taken out.

art b
 
Art,

First, are you sure that the original holes in the adjusting screws are not hex? I have seen photos of a couple of chucks that were that way.

Second, in order to remove the adjusting screws, I think that you have to split the chuck body (disassemble it).
 
They are all squared it looks like the were drilled and then rotary broached. the chuck doesn't com apart, it looks like there are plugs pushed into the back that hold in the screws, what i was thinking about doing was removing the jaws and trying to drive out the plugs. But even then I'm not sure what can be done to provide adjustment besides welding small bolts into the rounded out holes.

I'll post a picture tomorrow of the the chuck, I had assumed that all the atlas 4 jaws would have been made the same.

Art B
 
Yeah. My apology. I guess that I was thinking about the 3-jaw. Removing those plugs would be a sticky proposition. And replacing them only more so. I don't really have any suggestions of how to go about it, other than to look for something commercially available and cheap enough to buy four of them that already has the proper size square socket and that was large enough on the OD to turn for a press fit. Buying the proper size square broach would be pretty expensive.
 
That chuck says Made in England on it. Maybe not an original Atlas?

-frank
 
AFAIK, Atlas didn't make motors and they didn't make chucks.
 
I've often wondered about this. On a 4J chuck that I had, the thrust bearing that centers & locates the screw (what you call plug) was obviously pressed in from the rear. One of them was sitting proud & I tapped it in to equal depth of the others. I assume they must come out, but how? Tap from the front? If you find a rebuild link, please post. Now I'm curious. (screen grab from Gator brochure).

12-28-2016 0002.jpg
 
It appears that one might be able to make a special wye-shaped tool that would press the plugs (bearings) out. Or simpler, drill and tap the back of each plug and pull them out. Before doing either, I would number them (and the holes) and scribe a line through the center of each plug and out toward the OD of the chuck for witness marks to align them for re-installation. And of course locate replacement screws.
 
wa5cab said:
AFAIK, Atlas didn't make motors and they didn't make chucks.
Click to expand...

Thanks for that snippet Robert , I was wondering how one or both of the 3 & 4 jaw chucks on my 1943 Sphere cum Atlas that appears to have been built in & shipped complete from the USA were supposed to be the originals as they are also made in England .

I wonder ... Robert do you have any references or paper work relating to a few crates of British aka " Made in England " chucks being sent to the USA prior to say 1943 ?

I'll see what markings are on my chucks for I think that there is a makers name on one of them .
 
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