"Lloyd E. Sponenburgh" wrote:

I'm doing a cnc conversion on a 13x40 gearhead lathe.

My Z servo will be belt driven, so I think I can handle that.

Do any of you have a recommendation for a zero backlash coupling for the X
drive, which will be direct?

(metric AC servos)

LLoyd

That depends on how accurately you can mount the servo. The big CNC
machines I used to work on had rigid couplings with precisely located
motors. For a retrofit you are probably looking at a coupling that will
accommodate some misalignment. I'd look at the helical couplings or the
flex disk couplings. I wouldn't even consider anything like the lovejoy
or similar with any sort of insert.

Try Mcmaster.com, flexible shaft couplings, catalog page 1165.