WTB 3 jaw 4” chuck 1”-8tpi

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problematique

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I need a 3 jaw chuck for an atlas/craftsman benchtop lathe. I have one that requires an adapter and it’s running at almost 20 thousandths out. I bought a new adapter from allindustrial but the three hole pattern doesn’t match. I’d love to find a chuck that has integral threads and doesn’t require an adapter. I don’t care even slightly about the cosmetic condition it’s in. Please let me know what you have or where i might look for one. I was coming up short on ebay. The o.d. of the chuck i have is just over 4” so i’m assuming it’s a 4”. It’s a 1”-8tpi.

Thanks for taking the time to look. I appreciate it.
 
I forgot to mention that i don’t care about brand. I’m hoping for nicely functional and not crazy expensive. Thanks again!
 
You can drill new holes in your new adapter plate that are on the correct bolt circle but 60º offset from the existing holes. Mounting holes for adapter plates aren't critical as to location as the registration is made on the central counterbore. Your old adapter plate can be used as a template for locating the holes.
 
The OEM chuck on my Atlas/Craftsman 6x18 was a one piece chuck but it has 1"-10 tpi threads.
 
Then you must have a 101.21400 or 101,21200. For some reason (probably because it was the common thread on small 3-jaw chucks back in the '30's), when Atlas started building the sleeve-bearing 101.07301 for Sears in the mid 1930's, Sears insisted upon a spindle nose thread of 1"-8. And for some reason Atlas made the threads 1"-10 for their own 612 and 618. When the 101.07301 was discontinued in 1957 and replaced by the 101.21400 and later the 101.21200 (same as the 618 and 3950 except for badges), the spindle nose threads were changed to 1"-10.
 
wa5cab said:
Then you must have a 101.21400 or 101,21200. For some reason (probably because it was the common thread on small 3-jaw chucks back in the '30's), when Atlas started building the sleeve-bearing 101.07301 for Sears in the mid 1930's, Sears insisted upon a spindle nose thread of 1"-8. And for some reason Atlas made the threads 1"-10 for their own 612 and 618. When the 101.07301 was discontinued in 1957 and replaced by the 101.21400 and later the 101.21200 (same as the 618 and 3950 except for badges), the spindle nose threads were changed to 1"-10.
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By the tag on the machine, it’s a 101.07301. My first thread here was asking about that very thing. I borrowed thread gauges and a 1-8 tap and it’s correct for mine.

I’ve seen listings for 3” chucks for wood with the 1-8 thread. Does a chuck for wood have excessive runout compared to a chuck for metal? Are the jaws different? They look similar.
 
OK. Then you need the 1"-8, Something that you wrote earlier seemed to imply that you had one of the later machines.

The adapter plate does add one more group of bolts that have to be measured. I may also add between 1/4" and 1/2" to the chuck length. Which is generally undesirable.
 
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