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Heard a guy swearing by single-use drill bits the other day
Was helping a buddy overhaul a Cessna 172 engine at the hangar near Detroit last Tuesday. This older mechanic kept saying you gotta chuck the bit after every three holes or you're asking for trouble. I told him I use mine till they smoke and I've never snapped a fastener in 12 years. What's the real downside to pushing a good carbide bit past its prime?
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dylanmurray1mo ago
That older mechanic might have a point about certain jobs but three holes seems way too cautious for carbide. I've run the same bit through maybe 15 holes in 4130 chromoly without it even dulling. Though I did have a cheap HSS bit snap on me last month on the 4th hole and it cost me two hours of drilling out the broken piece. So maybe there is SOME truth to swapping them out on critical fasteners where you can't afford any screwups.
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taylor.amy1mo ago
4130 isn't chromoly though, that's 4140.
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finleyh891mo ago
@taylor.amy actually made me rethink this, I used to lump all chromoly together but they're clearly different alloys.
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