Quote Originally Posted by John S View Post
Industry hardy ever uses centre drills now, they use spotting drills very short fluted and stiff drills with a different angle on them and it's well worth buying a couple of the smaller sizes to replace centre drills.
Bought some TiN coated 4.8mm stub drill bits in cobalt HSS.

I tried starting a hole edgeways through the teeth on an aluminium timing pulley and watched the bit bend like a banana

I went up and down a few times to see if it could straighten itself up but it didn't, then I reached for one of my trusty old Slocombe's which put me back on true instantly.

Did I buy the wrong thing? :confused: