New Atlas owner

Buckshot, correction,

I actually have three (not two) 6" 3-jaw chucks. The one that usually sits on the machine is, as I wrote before, the Buck-style Pratt-Bernerd with 2-piece reversible jaws. The 3rd one, made in West Germany, has an auxiliary 1-1/4-8 thread on the back to lock it to the spindle so that it can run in reverse safely while machining. I don't think that it has ever been mounted on the spindle but once, right after I got it. I installed it once to confirm that it fit OK. Unless you are rich, or have a current job that actually needs it, I wouldn't suggest that you buy one JIC.
 
One of my chucks is 1 1/2 x 8tpi and the other is 2 1/4 x 8 tpi. All depends on which lathe the chucks were made for. My 8" with 1 1/2 x 8tpi came with my my craftsman 12x36 lathe. The other chuck is a Logan that I bought at an auction for $40. Chucks that fit on the spindle of the smaller lathes typically used by hobbist and small shops sell for more than chucks for larger lathes.
 
buckshot said:
Are all or most 8 inch chucks 2 1/4 or are there some at 1 1/2 ?
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It doesn't go that way.

The thread matches the lathe spindle threads, not the chuck size. So any sized chuck can have nearly any sized spindle thread or backplate. It depends on what machine the chuck is going to be installed on.

But when shopping for used chucks, you're stuck trying to match whatever the lathe spindle thread is to whatever chuck you have available to you.

Chucks are something I try to buy "new" now. I'm done fighting with worn/sprung/rusty/damaged used chucks. I just bought a NOS 10" Atlas independent 4 jaw chuck for my TH42 and I wouldn't have it any other way. They're still out there, you just have to dig them up....
 
buckshot said:
Are all or most 8 inch chucks 2 1/4 or are there some at 1 1/2 ?
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The smaller group of lathes like the Atlas, South Bends and Logans use the 1 1/2"x 8 mount. The through hole is 5/8"ISH and that really limits you for longer work Through the spindle. 8" chucks are the next step up as are the lathes and with that the through hole is larger and the spindle can handle a M 4 taper so the 2 1/4" mount is used. The point being why the need for an 8" chuck on that lathe? Your'e limited by the through hole with a large chuck. Why not a face plate with 1 1/2" x 8 TPI that was designed for those lathes and work with that.
 
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Charles scozzari said:
The smaller group of lathes like the Atlas, South Bends and Logans use the 1 1/2"x 8 mount. The through hole is 5/8"ISH and that really limits you for longer work Through the spindle. 8" chucks are the next step up as are the lathes and with that the through hole is larger and the spindle can handle a M 4 taper so the 2 1/4" mount is used. The point being why the need for an 8" chuck on that lathe? Your'e limited by the through hole with a large chuck. Why not a face plate with 1 1/2" x 8 TPI that was designed for those lathes and work with that.
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This is some really good advice.....and thanks for it.....I have the Crafsman 6 inch chuck that came on it and just now took it apart to try to find out why it will not hold the work tight....I could not find anything wrong, cleaned it, greased it and put it back together....that's when I found the Craftsman part number 383.22990 on it and came in to look it up.....I have NO high hopes for it but I will hang it back on and try it out....I am quite sure I will be quickly shopping for another chuck.....Thanks again for your feed back....
Have fun,
buckshot
 
buckshot said:
This is some really good advice.....and thanks for it.....I have the Crafsman 6 inch chuck that came on it and just now took it apart to try to find out why it will not hold the work tight....I could not find anything wrong, cleaned it, greased it and put it back together....that's when I found the Craftsman part number 383.22990 on it and came in to look it up.....I have NO high hopes for it but I will hang it back on and try it out....I am quite sure I will be quickly shopping for another chuck.....Thanks again for your feed back....
Have fun,
buckshot
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Hi, Thanks. I don't put any grease on my chucks because it will hold the chips on / in the scroll. I just give it a shot of WD40. I change the holding jaws from in to out holding often for different needs so I alway clean the scroll and jaws regularly. Is it possible the jaws in your chuck were not installed in the correct order?.
 
That isn't necessarily true. For example my 6" Pratt-Burnard has a grease fitting screwed into a recessed hole in the OD.
And no opening between the ID and the scroll.

The chuck body is also stamped with 1, 2 and 3. And the numbers on the jaws have to match the numbers on the chuck body. It is possible to meet that criteria and still not have them properly installed but a cursory inspection will reveal that they are out of sequence. Just remember that the last one to be removed must be the first one re-installed.
 
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wa5cab said:
That isn't necessarily true. For example my 6" Pratt-Burnard has a grease fitting screwed into a recessed hole in the OD.
And no opening between the ID and the scroll.

The chuck body is also stamped with 1, 2 and 3. And the numbers on the jaws have to match the numbers on the chuck body. It is possible to meet that criteria and still not have them properly installed but a cursory inspection will reveal that they are out of sequence. Just remember that the last one to be removed must be the first one re-installed.
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Hi, I have to think that the grease fitting on the Pratt-Burnard chuck is applying lubricant to the gearing behind the scroll and not the scroll face itself. In lieu of grease fittings I drip oil around where the key go's to lub the gearing. As for the jaw numbering, in some cases on other chucks the numbers are stamped in invisible areas that until the jaws are removed cannot be seen. I see that on the three jaw Imports. If you have a chuck with no visible markings, paint stick mark them in the location they are in before removing the jaws. On my 6" D mount # 3 comes out first and back in last. On my 10" Union Manufacturing Co., Skinner, and Craftsman the chucks are the numbered on both the case and jaws are visible before removal. Thank's very much for your reply.
 
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