Bertie Pittman writes:

I wondering if anyone knows how drill bits are hardened.

Enco sells drill rod of three kinds:
http://www.use-enco.com/CGI/INSRAR?PMSECT=750

Air, Water or Oil Hardening.


Hmm. Looking at the cost of 3/4" by 36" drill rod, I see

$9.09 Oil Hardening (Sale - was $16.79)
$8.19 Water Hardening (Sale - was $12.28)
$40.50 Air Hardening

I'm guessing your drill bit isn't air hardened.

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