Threading chart

[J. Tranter]

Does anyone know where to find a metric threading chart? You know the ones that tell you what drill to use with what tap.
John T

 

[mklotz]

Tap drill size = Major diameter - pitch

example: 6 x 1 mm tap

Tap drill size = 6 - 1 = 5 mm

This approximate formula will yield about 75% depth of thread.

BTW, it works for Imperial threads as well...

example: 1/4 - 20 tap

Tap drill size = 0.25 - 1/20 = 0.2" (#7 drill)

 

[rake60]

John

I keep this taped to the lid of my toolbox.