when i'm running a gcode my z axis seem to losing it.s calibration. it stepper don't change (in motor tuning) but when i tell it to move 3" to well move something like .40" and the z axis is moving alot fast to. now when it was cutting i did play with the feed rate. it has happen like three time now and everytime i have recalibrated the axis. i would like to trust it to put a good piece of wood in there but not there yet, but getting closer.

thank you

You could try reducing the 'velocity' and 'acceleration' settings for the 'z axis' in 'motor tuning'- don't forget to save the axis settings.

Tweakie.