SPYDERLK
Super Star Member
- Joined
- Feb 28, 2006
- Messages
- 10,160
- Location
- VA
- Tractor
- JD2010, Kubota3450,2550, Mahindra 7520 w FEL w Skid Steer QC w/Tilt Tatch, & BH, BX1500
T/D threads can be ground with CBN for steel or Diamond for carbide, so hardness is most an issue of wear and toughness,IMHO, what makes a GOOD tap (especially) is the metallurgy. It's tricky to get just the right combination of soft enough to be able to machine the tap threads properly, hard enough to cut well without wearing, and tough enough to not be prone to snap off. So, the very best quality tool steel combined with very precise heat treatment.