I have been trying to make chess pieces with the schools NC-65 lathe. The first 4 or 5 where great the they started coming out at different sizes, upon inspection i discovered the x axis was skipping then found a broken sensor on the machine. I replaced and broke that sensor (boilermaker by trade), so i got a fitter to help replace that sensor and we reassembled machine. This has taken place over 4 years. I still have the problem that the bloody thing is still moving erratically on the x axis. I have attached a video (zipped up) file any help will be really appreciated.

Check all the mechanicals first, I mean thoroughly check.

Check that axis slide is not tight or binding.
Check tightness of motor / leadscrew couplings.
If belt drive, check belt and pulleys for condition and tightness.
Etc.

Your video sounds like the motor is stalling.

Try reducing the X axis Velocity and Acceleration by 50% in Motor Tuning and save the changes. If this makes a difference then check that the X axis motor is getting hot (less than 60 deg.C) if it is not then increase the current setting (in the motor driver) by one setting and see if this makes a difference.

Try those for starters and report back.

Tweakie.

Thanks mate will do when i return to work.

Mark