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Re: Killer Drill Bit?
A while ago I was rebuilding an old Kohler 10hp engine from a wheel horse garden tractor and one of the head bolts snapped off. It was one of two that straddled the exhaust port so they were subject to trillions of extreme heat cycles and thus were extremely hard. I chewed up several regular twist bit that just squealed and barely made a mark. I went go a local loss and got an 1/8" and 5/16" dewalt cobalt drill bits. They were pricy at $7 and $15 but destroyed my snapped off hardened bolt easily
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