Hi Jazz,

I thought I would thank you for your help and let you know how I got on. I struggled to check the connections to the balls screws as there is a casting for the stepper in the way and I was not sure about taking things apart I don't understand. I set a dial gauge up (a 1" second-hand one made in China) setting the x and y to zero with the G0 moves you suggested for the x and y, the needle fell each time no further out than a thou graduation so I am assuming that is pretty good. Do you think that takes away the worry of perhaps loosing step and the coupler issue? The dial gauge is perhaps not perfect. I could attach a picture of the motor mounts if you thing I should investigate further.

Thanks ever so much you have helped me a lot.

Suesi