need some help...anyone ever tap 4mm screw holes?

[lincpimp]

Advancing the tap half a trun of so and then backing it out is a great idea. I always do this. I like to clamp the item to be threaded under the drill press, drill the hole, then chuck the tap into the drill press and manually turn it in. The drill press keeps the tap straight and true to the hole, and you can focus on slowly cutting the hole and not breaking the tap off. Do not try to tap the hole with the drill press under power, I pull the plug and open the belt cover and use the pulleys to turn the drill chuck by hand. Works every time, in all metals.