Nomenclature and Underneath Drive Qs

[RJSakowski]

I have an Atlas/Craftsman 6" lathe, c.a. 1957. My lathe drives from the rear with the OEM countershaft and motor mount. The lathe is installed on an OEM stand.

The headstock is as shown in post #8. Interestingly, the ways are relieved to match the opening in the headstock. I can think of no other reason for doing so than to accommodate a bottom drive system.

Personally, I wouldn't want botton drive on my lathe as it would make changing the belt from one pulley to another more difficult. The side mount does require an additional 7" to the rear though.

 

[wa5cab]

I don't know why I thought that you had a 10" instead of the two 12". Too many posts, I guess.

As far as what will, won't and may fit the later bed and hook up to the under drive:

The early 12" tailstock and base will fit with at most a slightly longer clamp bolt.

The early headstock will fit the late bed, probably with a slightly longer clamp bolt. I am not sure as to the two 1/4-20 bolts. Connecting the spindle to the under-drive will require cutting about a 4 x 6 or 5 x 6 hole through the bottom of the headstock and exchanging the 4-groove spindle pulley for the 2-groove one.

The carriage should fit with the addition of a 1/8" spacer front and rear. However, the traverse gearbox and handwheel will be 1/8" too high. And the carriage lock will require making a new lock plate.

The lead screw and right bearing are the same as those on the first version of the late 12". So they will fit.

Alternatively, you could mount the entire early lathe on the cabinet. It will still require cutting the hole in the bottom of the headstock. And you may have to drill new foot mounting holes and plug the old ones.

As far as changing the belt on the cone pulleys or the two-step pulleys, I think it's easier underneath or on the left end. But that's probably just a matter of which you are used to. But the under-drive is cleaner than inside the headstock.

 

[kcoffield]

I don't know why I thought that you had a 10" instead of the two 12". Too many posts, I guess.

Think you may have commented on this in other threads, but I was converting an older style 12" Craftsman with 3/8" thick ways to under drive on a 3996 style cabinet. I elected to do that with a 3996 headstock casting using the parts that would interchange and sourcing the ones that wouldn't. The deed is done and pretty well documented with the meat of it starting here for anyone interested.

New Caretaker of Two 12” Craftsman Lathes

Well, I'm back at it. I commented earlier about building a stand and a possible under drive countershaft conversion. I located the parts to do the conversion and a complete Craftsman lathe cabinet with drive assembly for a reasonable price, so off I go. It was my Grandfathers, Father’s, and...

www.hobby-machinist.com

Best,
Kelly

 

[wa5cab]

OK.