Re: Carbide counterbore
Gary Mason <carncrows2004@...>
If the gear is "case hardened"? and it sounds like it is, as you've managed to drill through the case hardening and into the gear with a carbide drill bit. Could you c/b for the screw head diameter plus clearance using another carbide drill, then put a shoulder at the base of the c/b using a hss drill bit ground flat with appropriate back rake to square off at the base.The steel should be reletively easy to drill below the c/h with slow rpm and good cutting oil.
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