[Condor51]

****Use it to quickly find integer pairs near a given ratio so one can select tooth counts for gear sets.****

Ahhhhh Heeeelp Nooooo - It's 1966 and I'm back in HS sitting in Mr Barry's Mechanical Drafting class!!!!

Just kidding.
I had Mechanical Drafting as a Major and made it and Engineering a career :-)

However 1966 was the last time I had to draw a gear.

[Paladin2]

Somewhere around here I have a DOS?/Win3.1? graphics file/program that lets you have a working slide rule right on your screen.

Amaze your friends. There was a Scientific American article (Amateur Scientist column IIRC) a few years back that went through the various, still useful, things a slide rule can do.