A15T Servo Rotary Broach Punch Tool 12mm Shank Spline Cutter Bit

All punch bit is positive tolerance +0.05mm, like 6mm, you get the bit is 6.05mm. Like A15T, you should use drill bit to do a hole 3.9mm. 2, Use punch bit A15T to working in the hole, at first, cutting feed slowly, like 300-500 is ok.