ACME thread chart per ASME/ANSI B1.5 standard for general purpose single-start internal ACME threads. Preferred tolerance classes for ACME threads is 2G.
Tap drill hole for ACME thread , drill selection shall be done to obtain a finished hole somewhere between maximum and minimum minor diameters. It shall be considered to be close to the maximum minor diameter to reduce the amount of material to be removed when tapping the thread.