One thing you could do to help the self tapping process is to make the hole tapered to help with a ‘lead in’. If you try printing a small pitch thread, make your layer height 0.04mm (one micro step) or multiples of 0.04, setting the layer height to arbitrary values other than a multiple of 0.04 asks the Z stepper to do things it cannot do - rotate to angles that it’s not designed to do. Roger. Sent from my iPhone 6