For Holemaking Application
Suggested Percentages of Full Thread in Tapped Holes
A common internal thread, drilled so that it results in 50% of full thread will break the external thread, before the internal thread will strip. A common internal thread drilled out so that it contains 100% of full thread is only 5% stronger than a 75% height of thread, yet it requires 3 times the power to tap.
These calculations are based upon theoretical values and are only intended for planning purposes. Actual results will vary. No responsibility from Kennametal is assumed.