I’m working on a future money-losing project in my spare time: a nice letterpress card that helps readers convert fractions to both decimals and metric measurements. Sure, you can make these conversions on your phone, but I prefer to see all the data at once, especially when trying to decide what size drill bit I need for a tricky peg.
Plus, it’s a fun graphic design project for that part of my brain that doesn’t get as much use these days.
As part of my research, I bought a bunch of old promotional posters. The things that salespeople would hand out to customers when they came to call. But my favorite find is this 1972 small slide chart from the Slide Chart Corp.
As the U.S. geared up to switch to the metric system, these sorts of calculators were everywhere. This one was a sample, made to show how you could get it customized with your company’s logo.
The slide chart makes 19 different calculations, plus has a graph that shows the difference between Fahrenheit and Celcius. It’s almost useful. It converts inches and centimeters, which isn’t quite what woodworkers need (I’d prefer inches to millimeters).
But it’s fun to play with, and I’ll keep it at my desk.
The best part is the little slide window that converts horsepower to metric horsepower. Are metric horses stronger? Look for yourself.
— Christopher Schwarz
P.S. I hope to have this letterpress card available for the holidays.