Hi JP - two things to do 1) run a very shallow pocket and measure it, you can use say a 10mm drill as a pin in the hole to check 2) check you axis calibration, generally its your axis calibration that needs adjusting. If the calibration is correct then you have to start looking for mechanical issues. If the light cut is correct then do a deeper one until you get a hickup. This shows the machine has some issue mechanically... Peter