Welcome to Eric's Slide Rule Site Greetings! This site contains scans and descriptions of my collection of slide rules, along with several pages of (hopefully) useful background information. I haven't been actively collecting new rules for several years now, but I have kept the site up as a resource for others. If you would like to make a donation to my server/registration fund, please see my Donation page. Thanks! All the high resolution scans have been reduced to 75 dpi, so what you see on the screen should be roughly the actual size of the rule. Please don't use them anywhere else without letting me know first - thanks!

Looking for flashlight reviews? Please see my Flashlight Reviews site.

Slide Rule Resource Centre

• Introduction to the Slide Rule
  Background on logarithms, history of the slide rule, and how it all works. (Updated November 3, 2001)
• Types of Slide Rules and their Scales
  Overview of the major categories of slide rules, and descriptions of common scale labels and meanings. (Updated September 12, 2002)
• Slide Rule Manuals
  Some downloadable slide rule manuals from different manufacturers available on my site. (Updated May 25, 2002)
• Where to Buy a Slide Rule
  Some suggestions to help get you started in finding a rule of your own. (Updated December 1, 2002)
• How to Clean a Slide Rule
  Greatly expanded, features a new set of pages contains tips for restoring your slide rule to its former glory! (Revised November 27, 2002)
• Slide Rule Books
  Reviews of modern books for collectors, as well as some old slide rule instruction books. (Updated September 15, 2002)
• Slide Rule Online Links
  Features a heavily expanded section of slide rule links. (Updated June 15, 2008)
• Why Collect Slide Rules?

Special Feature - The Evolution of a Slide Rule

• Features the major design changes the K&E 4053 went through during its production cycle of over half a century. I'm now up to 19 uniquely different models of this rule! (Updated September 27, 2002)

Slide Rule Collection

Why Collect Slide Rules?

I suppose it does require some comment. In the history of the modern world, probably no other technological instrument was so widely used for so long, only to disappear virtually overnight. The slide rule's form and features were revised for centuries, and there are probably few people today over the age of 50 who didn't routinely use one in school or at work at some point in their lives. Yet with the advent of inexpensive pocket calculators in the early 1970s, slide rules quickly went the way of the Dodo. What's all the more remarkable is that today it is possible to pick up 140+ function scientific calculators for as little as $5!

For me, I guess slide rules carry with them a sense of nostalgia for earlier scientific times. When you use one, you get a much better feel for what numbers really mean than when you use a calculator or computer. They are remarkable technological instruments, built with precision and reliability in mind, and are as useable today as the day they were first made. Many are also intrinsically beautiful, with their celluloid covered wood, metal-framed glass cursors, and richly coloured leather cases. I didn't set out to collect slide rules ... but I find their incredible diversity and functionality amazing and intriguing. If you're reading these pages, then maybe you do too, and so no other explanation is required. In any case, I hope you enjoy the site!

If you're interested in learning more about collecting slide rules, check out The Oughtred Society. They are an international organization dedicated to the history and collection of slide rules and related calculating devices.

Sliderule.ca in the News

Sliderule.ca was featured in the technology section of the Los Angeles Times (June 28, 2001). The article was reprinted in several online newspapers, most notably the Nando Times and Pioneer Planet. Since the online links are often updated or removed, click here to see a scanned copy of the original article.

You might also be interested in following the discussion of the article that ensued at the technology site Slashdot (July 7, 2001). I now know first-hand what it means to get "slashdotted"!

A brief review of sliderule.ca has been reported in the online version of the technology business magazine Business 2.0, entitled "When Slide Rules Ruled" (July 18, 2001).

One link to sliderule.ca (January 19, 2002) that generated a lot of hits was from the online collection of unusual sites known as memepool. I guess slide rules strike a common meme among people (my apologies to Richard Dawkins for the pun).

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Site last updated on September 7, 2011 -
All material © 1999, 2008 by Eric Marcotte.
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