Straight vs helical gashes on hobbing cutters

[spigor]

Does anybody know why are straight gashes on hobbing cutters so seldom used? I read in a book then if lead angle is less then 6 degrees than straight gashes are OK, but in reality I have seen hobbing cutters with lead angle less then 1 deg. and helical gashes. Why's that?

 

[MikeHalloran]

I think it has to do with trying to induce the chip to leave the gash, e.g. off to one side, rather than just curling up tight and sticking there.



Mike Halloran
Pembroke Pines, FL, USA