- Joined
- Apr 8, 2013
- Messages
- 1,982
It's amazing how I can screw up something I've done countless times. EVERYBODY knows tap drill for a 5/16x18 hole is an F drill at .252" or thereabouts so why look anything up. I've done this countless times. AFTER breaking the tap off in the piece I crack open the machinery handbook. It seems that the drill size changes with material thickness, DUH. As I'm going into .500 plate the recommended tap drill is .262" to .268". Five more fingerprints on my forehead. I'm running out of room.
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