Conical lock hole Conical lock hole strong locking. Sharp and hard round threading die Made of high-quality alloy tool steel overall quenched, integrated molding processing technology. Sharp and hard tapping thread, wear-resistance.large capacity chip removal hole, smooth chip remove. Please be sure to take protective measures when working, you need to wear goggles and protective gloves. Before tapping confirm whether the diameter of the die is appropriate. Be sure to select the appropriate cutting oil for the complex tapping process and apply anti-rust oil for maintenance after use. It needs to be reversed every 1/4~1/2 circle to facilitate the chip discharge from the chip hole.