I've got a Champion 10" lathe (made in Cincinnati), and it has a 1.25" x 8tpi spindle nose (with a slight taper). I found tons of 1.5" x 8tpi parts, chuck backplates, etc. But the 1.25" parts are more rare. I did find a 1.25" to 1.5" adapter, but I was wondering if there are any gotchas or issues that come with using an adapter like that.
Going "from backplate screwed onto nose" to "backplate screwed onto bushing, screwed onto nose".
Want to use a 6-jaw scroll chuck that already has the 1.5" x 8tpi backplate.
Look for either UNdrilled blanks or 1"-10 tpi.
Shars, CDCO, & H&H Industrial bring them in from China. Even the 1"-10 tpi should clean-up about right for threading to 1 1/4"-8? Zoro carries them, too. Around $35 brand-new?
As to the bushing? Prolly OK for a 6-Jaw. Those are only meant to be used for light cuts on thinwall tubing or easily distorted rings, not for holding bar nor heavier turning as 2-J, 3-J, or 4-J are.
A small lathe of this age does not DO high-stress turning in any case.
So the 6-J shouldn't ever transfer much stress into the bushing's threads.
The OTHER option would be to make an adaptor to a more common, larger, size and LEAVE on the spindle. With brass-tipped grub screws, even. One that South Bend used, for example.
That will be most accurate if turned and threaded
in situ. With care.
And then.. plenty of used and new goods will go right on to it. Stock backplates or "integral" back, either one.
And you can still remove it if you must do. That part is not always easy with Loctite?
