Broken centre drill recovery

[John S]

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:

Here's a spotting drill

http://cgi.ebay.co.uk/3MM-NC-SPOTTIN...mZ140320534140

No connection with the sale just came up in a search. Note the very short flute length to give rigidity.

John S.