Following the Rules — A Slide Rule Collection
Go to the Introduction
| New to slide rules? | What is a slide rule? | What is a logarithm? | How do you use a slide rule? | What do all the scales mean? |
| Returning to the site? New Rules! |
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Reference Material | Some History of the Slide Rule | Site Tips |
| Vignettes | 41 blog-like articles and stories about slide rules, calculations, and collecting |
| Last Update | Vignette Title | Abstract |
|---|---|---|
| 2024 Sep 07 | K+E Mystery Rules Update | The earliest date for these rules of mystery just got a little earlier. |
| 2024 Aug 29 | Slide Rules for the Sikes Hydrometer | But, how much of that liquid in the barrel is actually alcohol? And, of course, how much tax should be collected? |
| 2024 Aug 18 | Power Rules | Log-Log scales are used for raising numbers to arbitrary powers. Their scales and use are explained. |
| 2024 Jul 14 | The French Connection to a Mystery Rule | The scales found on a K&E Mystery rule are the American version of the French Beghin rule. |
| 2024 Jul 10 | Kolesch Rules | This New York City company sold German import slide rules, including some with special scales. |
| 2024 Jul 09 | The Aver-O-Matic | Patented and produced by a young Colorado entrepreneur, this device can calculate the average of up to 10 numbers as well as compute scores of multi-problem exams, based upon the number missed. |
| 2024 Jun 17 | Scale Wars | The K&E Duplex rule introduced in the 1890s was a major improvement to the standard Mannheim. How did other makers react? |
| 2024 May 26 | The Acu-Rule from Wabash | How did a Wabash, Indiana, school supply company come to sell Acu-Rule slide rules, while Lawrence Engineering was making similar items just down the road? |
| 2024 Mar 25 | The Scofield Engineer’s Slide Rule | With the help of Thacher, a bridge engineer delivers an inexpensive but powerful slide rule at the turn of the 19th century. |
| 2024 Feb 05 | Chicago Rules | Chicago companies played a strong role in the development of US slide rules. |
| 2024 Jan 31 | America’s Earliest Part II | American-made slide rules before Palmer’s Computing Scale? Enter the Belcher Brothers. |
| 2024 Jan 17 | American Favorite Part II | Further study reveals new insights (to me) into the early K&E American, Favorite, and Mannheim brands. |
| 2024 Jan 10 | How Do You Byoutou? | A WWII-era Hemmi slide rule was used to train junior officers in the basics of ballistics calculations, including how to lead moving targets. |
| 2023 Dec 14 | Gauging Electro Rules | The electro rules were early specialty devices derived from the Mannheim design, and helped introduce log-log scales to modern slide rules. |
| 2023 Sep 25 | Thacher’s Calculating Instrument | Thacher’s cylindrical ‘Calculating Instrument’ (patented 1881) was sold by K&E until the 1940s, yielding the accuracy of a 30-foot linear slide rule. |
| 2023 Aug 11 | Following the Balloons | Essentially a stadia-type calculation, slide rules were used to compute meteorological parameters through sightings of pilot balloons in flight. |
| 2023 Jun 27 | Carpenters vs. Engineers | Those folding 2-foot rules with brass slides and logarithmic scales – what are they and how do they differ? |
| 2023 May 29 | Dietzgen Rosenthal Nestler Prototype | Online images of a $7 Dietzgen for sale just didn’t look right. A Nestler prototype version of Dietzgen’s update to their Rosenthal model was uncovered. |
| 2023 Apr 08 | Gauging and Excise Tax Slide Rules | Ever wonder how to calculate the amount of liquid in that funny-shaped whisky barrel? |
| 2023 Mar 10 | America’s Earliest Slide Rule | Palmer’s Computing Scale of 1843 is often given this title. |
| 2022 Dec 23 | Spring Calcs Eternal | Besides illustrating several spring calculation slide rules of various manufacturers, the formulas used are also derived! |
| 2022 Dec 10 | Out of Proportions | Determining ratios and performing proportions calculations are basic functions performed by a standard slide rule. |
| 2022 Jun 20 | Vector/Hyperbolic Calculations | Imagine finding the tangent of a complex number. You really can do this. With a slide rule! |
| 2022 Jan 05 | Stadia Rules | Surveyors in the field and office used special slide rules with special trigonometric scales. |
| 2021 Dec 12 | Helical Slide Rules | Accuracy is gained through helical curves on cylindrical surfaces – the Otis King and Fuller slide rules. |
| 2021 Dec 05 | The Early American Favorite | Cleaning of a $10 slide rule reveals a fairly early K&E. |
| 2021 Oct 03 | Lt. Shaw’s 4097D | A simple search for a common model uncovers a slide rule very likely owned by a major player in the construction of the first US nuclear warships, the U.S.S. Nautilus and the U.S.S. Enterprise. |
| 2021 Oct 02 | Rule Change 4092-3 | A rare transitional scale arrangement for the K&E Model 4092-3 was just sitting in the collection all along. |
| 2021 Aug 10 | K+E Beginner’s Rules | Keuffel and Esser sold slide rules designed for beginners almost from the beginning. |
| 2021 Jul 01 | An Early Home-Made Spring Calculation Slide Rule | While slide rules for designing springs became available from the major makers around 1950, Baetzmann introduced this one almost a decade earlier. |
| 2021 Jun 20 | A K+E Rule of Mystery | Certain K&E slide rules with no model number remain mysterious. |
| 2021 May 15 | British Thornton Special Scales | Hard to get that last digit on your S/T scales when the values get close to one? The Thornton Sd/Td scales can help. |
| 2021 May 01 | Getting to the Root | You know how to use A&D or B&C to find the square root of a number; but can you solve a quadratic equation on a slide rule? |
| 2021 Mar 01 | The Long and Short of It | How the accuracy in calculations using logarithmic scales scales with scale length. |
| 2021 Feb 08 | Hemmi 153 Scales | Now imagine finding the tangent of a complex number through the use of the Gudermannian function. Don’t worry, it’s all explained… |
| 2021 Feb 06 | A Boykin Discovery | Can you only find significant slide rules online? It still pays to visit your local antique stores. |
| 2021 Feb 05 | Fermi’s Golden (Slide) Rule | What slide rules did Enrico Fermi use? A family member gives us insight. |
| 2021 Feb 04 | Rules of Engravement | Slide rules were used in the layout of newspapers and magazines in the last century. |
| 2021 Feb 03 | The Original 4083 | Before the development of the vector slide rule 4083-3, the 1916 K&E model 4083 was an early 16-inch Duplex general purpose rule. |
| 2021 Feb 02 | Rules to the Moon | Pickett earned their place in US space history with their lightweight metal slide rules. |
| 2021 Feb 01 | A Favorite Rule | Everyone should have a slide rule that just feels right. The Faber-Castell Model 1/54, a finely-made general purpose Darmstadt rule, fits the bill. |
| Collection Photos A chronological look at the slide rule collection |
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Rule Makers The collection, organized by manufacturers |
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Special Groupings Subgroups, such as oldest, youngest, most scales, specialty slide rules, … |
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| A Searchable Table of the entire collection |  |
A Data Sheet for each rule |
Welcome!
This DataFrame-driven web site presents a personal collection of slide rules as well as other useful information about slide rules, their operation and use. Click the arrows (> and <) on each page or use your keyboard’s arrow keys to move between pages. Use the left navigation pane or the quick links on this page to go directly to a particular chapter or subject.
-Mike Syphers
| About This Web Site | About the Author | |
| The Oughtred Society | United Kingdom Slide Rule Circle | International Slide Rule Museum |
| 05 October 2024 |