Threading lead screw slop

[Robert_Duncan]

I have a 16x60 Carrol-Jamieson lathe that I have owned for about 3 months now. It has a separate apron power feed shaft and threading screw.

The threading screw can be moved left and right by hand longitudinally about 1/2". This does not seem right. I guess as long as I bottom the shaft in the proper direction before beginning a threading operation it would make repeatable thread cuts.

Should I live with it (it is a 59 year old machine) or try to make a shim to remove the slop?

[AndrewMawson]

Robert,

There is often some sort of collar arrangement around one end of the leadscrew bearing bracket (could be either end) to limit its endfloat.

I would suggest that you need to reduce it to a few thou.

[Matt_Isserstedt]

I think I'd look into the play. Something probably isn't right and a closer inspection upon disassembly would help.

You are correct that "pulling" out the backlash will make it repeatable but then there's that one time you forget.........

Hello from another Ann Arbor boy (1980 to 1998)

[GeorgeGaskill]

and crank the carriage back and forth; look to see if the lead screw is moving with the carriage and how much it moves.

I expect the lead screw will not be moving much, which implies most of the wear is in the half nut/lead screw relationship. Usually the half nut wears a lot faster than the lead screw so a cheaper piece can be replaced to correct the slop.