Re threads and an entertaining read I can thoroughly recommend Simon Winchester's book Precision - a bit of a Cooks tour through increasing engineering precision in the last 100yrs or so.
Threads drive me insane - pitch guages, micrometers, a book referencing pitch, major diameters etc helps a bit. Metric is a 'Bit' simpler but even then you get so many different variants, I think I have them all then Murphy comes...... 😜, in Aus we have the hangover from Imperial UK, imports from USA and now metric. We are totally f*****d. 😂