Interleaved drill size chart

[mklotz]

The stupidity of drill nomenclature in the USA is legendary. Arbitrary letters and numbers with no underlying formula provide no information at all about the size of the hole the drill will make. Fractional designations provide size but in a mathematical form (rational fractions) that must be converted to decimals in most machining applications.

The solution is an interleaved drill chart where all these nomenclatures, along with metric, are arranged according to hole size.

This outfit generously provides just that...

https://templatelab.com/tap-drill-chart/

Scroll down to the chart with blue highlights provided by Amtek. This is a downloadable pdf that can be printed on a single 8.5 x 11 page. Necessarily, the print will be small so have your bifocals polished.

Oh, and it indicates the tap drill size for 75% DOT for most common thread sizes as well.