ISRM is the world's largest free digital repository of all things concerning slide rules.
There are over 6550 Images or PDF's (not counting thumbnails) in the ISRM Galleries

The ISRM is dedicated to the Students, Educators, Scientists and Engineers of the Past and Those Still Present, and to promote the lost art of Numeracy by providing resources and slide rules for education and other historic institutions. ISRM is a member of the American Association of Museums and the Association of Northern Front Range Museums.

Well-used Calculators for Hairy-Eared Engineers*
ISRM was featured in an exhibit at the Louisville Public Library, Louisville, Colorado.

Welcome! Click Here for Introduction, Museum Mission Statement, and Donation Policies

New and Recent Additions to the Museum

ISRM congratulates the Oughtred Society on your 20th Anniversery! The above cake, copied after a Pickett slide rule, was presented to the membership at the IM 2011 meeting at MIT.
ISRM is now administering the International Slide Rule Championships. Any collector group, school or engineering association are invited to participate. Problem sets provided by ISRM as well as the Medals to be awarded to the local champions, FREE! The first innagural contest in was Rose Suarez's Mathematics and Research Class in Half Hollow Hills, NY. (on Left). Kristen Fouss's Pre-calculus class at Anderson HS in Cincinnati, Ohio had the most recent champions (on right).
The Oughtred Society held its annual meeting in Las Vegas Nevada and hosted the 2010 International Slide Rule Championships. Nine finalists from a large group of attendees fought for the top three trophies. Winners were Bennie Tschoerner, Paris, Texas,1st place; Riki Nakamoto, Oahu, Hawaii, 2nd place; Carl Schwent, Phoenix, Arizona, 3rd place. Honorable mentions were: Bob De Cesaris, Gary Flom, Gerd Keuffel (of the K&E legacy), Bob Koppany, and Kate Matthews. Any collector group, school or engineering association are invited to host an ISRC contest.
Mike Konshak, ISRM Curator presented a symposium on slide rule history, manufacturing processes and use to the Northern Colorado No. 354 chapter of the Society of Manufacturing Engineers in Longmont, Colorado. Mike was presented with an award by Andy Keller and Don Larsen and many slide rules were donated to ISRM by Andy Keller from his personal collection. More pictures.
  • There is a newSearch Engine for this website which will assist you in your research of slide rules. This Search engine is provided by JRank
  • There are new additions to Slide Rule Scales which you can use to build your own slide rule. The latest uses a CD/DVD case to support a circular slide rule (by Ying Hum of Canada)
  • A new gallery of Technical Slide Charts and Disks. Over 700 pre-programmed calculators made of cardboard or plastic film for designed for specific repetitive tasks and offered as promotional items.
  • A new gallery of Slide Rule Who's Who - Past and Present. Slide rule manufacturers, inventors, dealers and collectors has been added to the museum.
  • A new gallery of Historical Photos of People with Slide Rules. Over 400 Photographs and Ephemera showing slide rules in action has been added to the museum.
  • A new gallery of Patent Database.. Downloadable Patents as early as 1851 to the present day, involving logarithmic calculating devices. There are currently over 900 worldwide Patents available for downloading in PDF file format.
  • A new gallery of Herman van Herwijnen's Slide Rule Catalogue. We've added clickable thumbnails to over 2200 slide rules and slide charts.
  • The ISRM's Free Slide Rule School Loaner Program now has many new sets for use in the USA, Germany, Netherlands and Japan. Teachers may now keep them out for a full semester! The program has been expanded to include Home Schoolers. Students! - Be the first in your class to get your teacher or school to participate and receive a FREE SLIDE RULE that you can keep and treasure forever!
  • Free Web Hosting for ISRM Associates Put your collection here!

Students from the University of Waterloo in Ontario, Canada created an exhibit for the annual Knowledge Integration (KI-X 2011) exhibit using slide rules donated by ISRM. Click on the banner for more information.

Dr. Barbara Rooker of the Joplin, Missouri K12 School System, introduced students to slide rule math during 2009 using ISRM's free loaner program. Click banner for more pictures:


Galleries

All slide rules are organized into one of the following
galleries (webpages) based upon the number in the collection
Demonstration Herman van Herwijnen's Slide Rule Catalogue
Rarities (Olde) Australia
Acumath Aristo
Faber-Castell Dietzgen
Geo. Richardson Scientific Inst. Co.
Graphoplex K&E Standard
Hemmi K&E Specialty
Pickett Post
Sterling Lawrence
Nestler Relay/Ricoh
and U.S. Brands
Slide Charts/Disks Soviet-Russia
Misc USA British - UK
Misc Europe Misc Japan
Military Mech Adders
Circular Misc World
The original specimens and files found in this museum prior to 2005 were donated to the Computer History Museum in Mountain View, California in for preservation and display. Take time to visit CHM when you are in the area. ISRM continues to expand.


This May 2006 article is the most recent publication on slide rules and it generated a renewed interest in collecting or in obtaining one of these mathematical works of art. Click on either picture to download a 17.25MB PDF scan of this article written by Cliff Stoll. We thank Scientific American for this ephemera. Meet Cliff in this entertaining YouTube video that shows talking about science and using a slide rule

This November 2005 article is a French publication on the history of slide rules written in French for Pour la science - Les génies de la science, novembre 2005-février 2006, p. 20-23. Click on either picture to download a 3.98MB PDF scan of this article written by Noël Jouenne who kindly submitted this to ISRM.

Two Bloom County (Opus) cartoons, by Berkeley Breathed, pertaining to the demise of slide rules. It was published originally in 1988 and later in "Classics of Western Literature - Bloom County 1986-1989" published by Little, Brown Company, 1990. It was one of the last known references to slide rules in the cartoon world.

Modern Logo's depicting Slide Rules


USAF Test Pilot School Patch
Edwards AFB California

Joe Miner, Official Mascot of
University of Missouri-Rolla
Purdue Engineer's Yell (1960's)
e to the x, dy, dx
e to the x, dx
cosine secant tangent sine
three point one four one five nine
square root, cube root, Btu
slipstick, slide rule, Yay Purdue

Contributed by Bruce Chelf,
Purdue Alumnus (The ISRM curator
subsitutes CSU for Purdue)


* Hairy-Eared Engineer - definition:
1) An engineer who's old enough to have hair growing out of undesirable places.
2) Who's been practicing engineering so long that he or she has already made all possible mistakes at least once.
3) A desirable person to have on a project to ensure the mission succeeds.
4) Quote: "Every project needs at least one hairy-eared engineer" Marvin B. Davis -1980.
(Marvin was one then and 25 years later, my barber can attest that I've finally made the grade).

Slide Rule Wallpaper

This wallpaper is a collage of many slide rules. It is 1240 x 1020, 582kb and I have almost every slide rule manufacturer and country represented. Save this file (Right-Click Save Target) and select it using for the background on your computer monitor. 'Right-Click' on your screen and select 'Properties', then 'Browse' to the file to change your wallpaper. I hope you enjoy it.

Astrological Nerd Signs - A Y2K Compliant Zodiac

Keuffel and Esser, the Slide Rule
Keuffel and Esser, the Slide Rule
September 24th ~ October 22nd

People born under the sign of the Slide Rule have a particular talent for extending themselves to handle new problems and situations. They are able to look at problems, both small and large, and immediately keep the basic details in proportion.

Elegant and dependable, Slide Rules are known for keeping their cool and never letting on that they're being pulled too far until they reach their limit and abruptly fall apart.


Not you? See where your birthday falls in Nerd Signs


Bennie Tschoerner
Paris, TX
NEWS: 2011 World (Texas) Championship Slide Rule Competition

The World Championship Slide Rule Competition held on March 12, 2011 in Irving, TX was won by Bennie Tschoerner, who was also 2007, 2008, 2009 and 2010 champion. Bennie lives in Paris, Texas and is a member of the Oughtred Society.

1st Place: Bennie Tschoerner using a K+E 4181-3
2nd Place is Brad Bradfield
(There were 2 entrants)

The competition consisted of a set of problems that needed to be solved within a given time limit. The winner who gets the highest number correct wins.

Congratulations to all participants from the Slide Rule Community and to Skip Solberg the Competition Director.

Proud Member of


1574-1660 William Oughtred Inventor of the Slide Rule

1831-1936 Victor Amadee Mannheim standardized modern scales

c1890 DUPA (Aristo) Class Germany

c1900 Englewood (NY) High School Students

c1905 IIT Classroom

1909 IIT Elect. Engineers

1934 Iowa State SR Class

1941 IIT Engineering

1942 Purdue Aeronautics

1952 Edwards AFB
Test Pilot School


1954 Hamburg, Germany

1956 Edwards AFB
Test Pilot School


1965 NCF Math Class

1970Colorado School of Mines

1976 Joe Pasquale (right) Weehawken HS, NJ now a Professor at UCSD

1997MIT SR Class

2006 UCSD SR Intro

Present Collector


Mike Konshak, the curator and webmaster of the museum, has been honored with the Oughtred Society Award for 2009. He was made a Fellow in this prestigious organization in 2006. It is an honor to be selected to be amongst the other current and past Fellows and Award winners. If you are the least bit interested in the history and use of slide rules you will want to join the Oughtred Society.

Copyright © 2003-2012 International Slide Rule Museum