Formula: Tap Drill Size
Type in diameter
(fractional 1/64 to 1 or decimal .015625 to 3.5)
, threads per inch, and select % of full thread.
Diameter
Threads Per Inch
% of Full Thread
Theoretical Drill Size
Nearest Standard Drill Size
50%
55%
60%
65%
70%
75%
80%
85%
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