Make your own circular slide rule

The slide rule is a simple but elegant mechanical calculator. A practiced user with a good quality slide rule can multiply, divide, exponentiate, take logarithms and perform trigonometric operations to three significant figures more quickly than with an electronic calculator. Below you will find a PostScript template and instructions for building your own pocket-sized circular slide rule, like the one pictured at left.

Templates and instructions

There are two files. Each is designed to be printed on a single 8.5 x 11 inch page at minimum 600 dpi resolution. The directions are in HTML.

This circular slide rule has the most essential functions of a scientific calculator. There are enough scales to let you do just about anything, but some things (like hyperbolic functions or tangents) require multiple steps. Think of it as a RISC processor!

You may freely share the templates and instructions, as long as you don't charge anyone for it or bundle it with merchandise for sale. Please keep the copyright notice intact.

What next?

If you enjoy using my simple circular slide rule, you will probably find even greater enjoyment using a professional quality instrument. I have a classic Keuffel & Esser Log Log Duplex Decitrig given to me by my wife's uncle, and It is a real treasure. If you are very fortunate, you may have such an uncle. Or perhaps you can find a slide rule in an attic or at a garage sale. Good slide rules like the K+E operate very smoothly, are quick to use, and typically last for many years. Sophisticated models have more scales than my simple circular slide rule, making for greater flexibility.

Here are some favorite slide rule websites:


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Last modified: April 14, 2007. Page maintained by: