Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - What Size Drill Bit???
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Old 06-04-2007, 07:53 AM
hemi43 hemi43 is offline
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Another way to find the tap drill size is to minus the pitch from the diameter.
i.e, 3/8-16 thread, .375 - .0625 = .3125 or 5/16
1/4-20 thread, .250-.050 = .200 or 13/64

to find the pitch divide 1 by the number of teeth per inch. Dan
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