Tap Drill Size Calculator


Tap drill size calculator was developed to calculate appropriate tap drill sizes and recommended cutting tap hole size limits for inch threads. Calculations are done according to the Machinery's Handbook and FED-STD-H28/2B-1991.

Desired thread size, internal thread class and length of engagement parameters shall be specified in "Input Parameters" table of tap drill size calculator.

Desired unified thread size can be selected from a list of thread sizes which are in the diameter range from 0.060 inch to 2 inch. For Internal thread class, selection can be done among the alternatives 1B & 2B and 3B. For general use, select 1B & 2B thread class. Read more here https://www.metalcuttingvision.com/tap-drill-size-calculator/