I’ve been a machinist for decades, and a shop owner for some of them. Over that time, I have written many little utilities to make life a little easier, so I don’t have keep delving into Machinery’s Handbook
or other references.
This app, which I use pretty much every day, is a compilation of some of those utilities, they include things like calculated tap drills, for UN, Metric, Pipe, NP and BS.
Threading, UN, Metric, Acme, standard and stub. All threads are CALCULATED to ASME/ISO standards,
you can enter nonstandard diameter TPI combinations and get the correct result.
Trig functions, Drill table with search functions, bolt hole calculations, taper calculations.
Conversion calculations, things like TPI to mm pitch, basic mm to inch, countersink depth/dia calculations.