We use a specialist tap for producing a coarse thread inside of a connector - thread is a 3-start 5/16 by 5TPI, square modified profile. We recently purchased some taps from a new supplier after the previous went bust. We successfully tapped the parts for many years with the taps from the previous supplier. The new taps however, have broken on first use, under our usual procedures. The tap is a tapered tap with three straight flutes, carbon steel. We are tapping a mild steel.
We have attempted tapping on a small lathe with a floating head, and also on a CNC lathe with pitch control set up. Sulphurised cutting oil has been used, we have tried different speeds, as well as correct and oversized pilot holes for the tap. Very frustrating as we have never had issues until now!
Any advice on the tap, procedure, or anything else would be greatly appreciated!
Thanks
Joe
We have attempted tapping on a small lathe with a floating head, and also on a CNC lathe with pitch control set up. Sulphurised cutting oil has been used, we have tried different speeds, as well as correct and oversized pilot holes for the tap. Very frustrating as we have never had issues until now!
Any advice on the tap, procedure, or anything else would be greatly appreciated!
Thanks
Joe