Calculating threadscalculator

As a rule of thumb, for Metric threads, the tapping drill can be calculated by subtracting the pitch from the diameter of the thread. eg for an M5x0.75 thread the tapping drill is 5-0.75mm = 4.25mm.

What iscalculating threadsin Excel

To calculate tapping drill size for metric threads subtract the pitch from the major diameter, Select the next larger standard drill size.

How to stop Excelcalculating threads

For Imperial (inch) threads the tapping drill size is calculated in the same way, diameter minus pitch. eg for 3/4.10 UNC pitch = 0.1, diameter = 0.75, tapping drill = 0.65 = 16.5mm.