My first slide rule

I grew up with electronic calculators and while I remember my uncle having a slide rule that I played with as a kid (didn’t know what it was at the time…it was just a neat looking thing with slide-y bits and numbers printed on it), I never used one until I got my first one in high school.

At the end of one of my high school math classes, I noticed the teacher using something that wasn’t a calculator to work out the grades on a test we just had. Intrigued, I went over and asked about it. He was using a slide rule, showed me some basic operations on it. He was calculating percentages faster on his slide rule than using a calculator. I thought it was just the neatest thing in the world. He reached into one of his desk drawers, pulled out a box, and handed it to me.

I had my first slide rule!

Ricoh No. 102 slide rule case
Ricoh No. 102 slide rule case
Ricoh No. 102 slide rule
Ricoh No. 102 slide rule

It’s a pretty simple beginner’s slide rule made of bamboo with a plastic reticle. It’s a single sided slide rule with a reversible slider. that has B/CI/C scales on one side and S/L/T scales on the other. Seems like this model would have been an inexpensive slide rule targeted at the student market.

The back side has some handy reference tables and formulas.

I taught myself how to use a slide rule and used it pretty regularly through my last year of high school and into my first couple years of undergrad. The main reason I stopped using it was that most of the problems became more symbolic, and the numeric problems I did get became complex enough that it was faster for me to use my calculator (HP-28S at the time). The slide rule stayed in the desk drawer for the rest of my undergrad and grad school.

Most of my calculations are done using spreadsheets now, but I pull the slide rule out every now and then for some quick calculations and to remind myself how to use it.

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