Thread: tap drill size
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christofire christofire is offline
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Default tap drill size


"Jim Thompson" wrote in
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1/4"-20 tap calls for 0.201" tap drill (13/64")

Into a steel 1/8" panel, tap is hard enough to turn that handles flex
:-(

Is that normal, or do I need to go up one or more drill sizes?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
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Measure the core diameter of the tap and go down a bit for eccentricity and
general wobbles. Alternately, try your larger drill on a scrap piece, tap
the hole and then inspect it with a magnifier - if the threads are
flat-topped you've gone too far.

Chris