hi guys...,.,.seems back to the drawing board for me. ive been trying to do some engraving on acrlic. everything is going fine, when after 10 minutes or so, the Z axis starts to drop rapidly. in a mattert of 1 inch of travel, it has bottomed out to the collett. chilipeppr says depth is .5mm. don't know if this is a shielding issue or not with the stepper motors. im using the stepper motor cable that came with the r7 kit. its like the Z stepper motor loses power and the weight of the spindle makes it drop. i have made many tests using a pen and this has never been an issue. now that the spindle is on and running, haven't made it past 10 minutes with out disaster.