This non-commercial website was an amazing 60th birthday present from my soulmate Ros. But the website name is thanks to another family member - our daughter Siân. When asked as a teenager what I did, she often told her friends: “My Dad? Oh, he collects expensive sticks of wood!”
When the latest PC/tablet is out-of-date inside 6 months, it may come as a surprise that the Rev. William Oughtred (1575-1660) invented his Circles of Proportion calculator around 1621. This analogue principle was in continual use for nigh on the next 400 years. My hobby is collecting and writing about this analogue calculating wonder - the SLIDE RULE. Over the years the concept was successfully adopted and adapted by many trades and professions. Remarkably being able to use such an elegant analogue instrument from a bygone age is still a licensing condition for all private and commercial pilots.
This website is a virtual “display cabinet” for my collection (as I uploaded it) of slide rules, slide charts and mechanical calculating aids plus a virtual “bookshelf” for my published articles - enjoy browsing.
|A.W. Faber-Castell||1/38, 2/66, 8/13, 8/14, 8/15 & 51/88|
|AHREND (Wed. J. Ahrend & Zoon)||642T, 649, 651, 690, 696, 698, 699 & 701|
|ALRO (All-Round)||101, 10 RL, Beton, Cycloop, GoA, Ha.C/P/Q/V, Ha TEX, Piret, Philips Calendar, Nomographie, Van Leer, Vonderlingenplaat & WeR4|
|AWF (Ausschuss fuer Wirtschaftliche Fertigung)||SR703, SR705-709, & SR754|
|Controller Calculator||200 R|
|DARGUE Bros. Ltd. / Simplon||Sub-Ivory SR-1 & SR-4 + Honduras SD10, WR-2A, WR-5 & WR-7|
|Fearns Calculators||Barber Shop Harmony Calculator|
|Fowler||Nautical, Artillery, Kearns & Mackay|
|Inglis||any FLASH RECKONER|
|ITAB (Internationaler Tabellenverlag)||Multicalor Flachheizkorper & Styropor-Vollwarmeschutz|
|IWA (Ingenieurbuero fuer wirtschaftliches Arbeiten)||15489 Harmonik|
|Johann Faber||180/080, 180/082, 9203, 9204 & 9204|
|Keuffel & Esser (K&E)||4081-3 Braille version|
|KOSMOS||Book: "De Rekenliniaal" - 11th & 12th Editions|
|L&C Hardtmuth / Classic||10" Series III|
|Lawrence Engineering Services||S-M (C.V. Ore) & Exposure (MIT)|
|LOGA Calculator A.G.||TF, T150, T300, O2 Calculator, 30 TxC & 75 Terminator|
|Nestler||RP 75, Kreisrechner & Disc-O-Lator|
|S.R.&S.E. (Slide Rule & Scale Eng. Co.)||- any -|
|Systeem Matthijssen||- any -|
|Unique||Junior, Study 500/700/900 & J180/181/182|
Those needing a “memory jogger” or is intrigued how such bygone analogue calculators worked, the International Slide Rule Museum (ISRM) offers an illustrated teach yourself course: “How To Use The Slide Rule”. Alternatively download the self-running 35mm “slide show” Training Programme with synchronised audio commentary I digitalised. Afterwards try out some test calculations using Robert Wolf's online simulation of the classic Nestler 23R wooden slide rule. If this gets you thinking about starting your own collection, then the UKSRC/OS “Beginner’s Guide to Collecting Slide Rules” is a must read.
For educators looking for maths related inspiration and teaching aids/material then you need to look no further than Nicola Marras’ slide rule inspired website. But if you are just looking for reference works/published books on slide rules try one of these inventories: List 1 or List 2.
The Bonn-based Arithmeum museum's current special exhibition (to May 2024) is a tribute to 17th/18th century forgotten mathematical & drawing instruments. The Sectors on display, some in cases & others parts of sets, are among the most beautiful and rarest that have survived to this day. The accompanying YouTube film is also well worth a watch.
Dutch maker ALRO is famous for its circular slide rules where the lid doubles up as a desk stand. Otto van Poelje has meticulously catalogued and photographed every model (disc or chart) ALRO ever made. At the recent online 2023 Int. Meeting the book was relaunched. Watch the short video clip about the book here … and order your copy here …
Engineers Krusse & Larsen developed a dividing machine that enabled Danish company DIWA to produce a range of slide rules. Early models were mostly Rietz types & made from mahogany. Later they moved to all plastic & sold other types & specialist models. Their heyday was the 1950s & 1960s. The business closed in 1979.
Check out my collection of DIWA’s here ...
It was time for a spring clean. Some information on this website needed refreshing and/or updating.
The changes were not major but I also took the opportunity to made the “look & feel” more consistent.
Tom Martin, one of the UKSRC's longest serving members, sadly passed away in hospital at the beginning of January. Tom was an international expert on all things Gauging, Brewing and Hydrometry. He was a warm-hearted gentle giant who would always freely share his knowledge with fellow collectors. Tom will be sorely missed.
Rod Lovett’s facility listing the slide rule models of 14 major makers has recently been expanded with 7 new image archives – click HERE to take a look.
Thanks to Jose G. Fernández collectors can now download free-of-charge English & Spanish translations of Rechenschieber im Wandel der Zeit - a book published in 2009 by Guus Craenen. It charts the development and evolution of the slide rule from 1787 to 1905. Click HERE to go to the download webpage.
Did you know a special model exists for each house of Hogwarts School of Witchcraft & Wizardry? Depending on your Gryffindor, Ravenclaw, Hufflepuff or Slytherin affiliations select your Harry Potter inspired sorcerous slide rule simulation from Robert Wolf’s website ...
Generically a slide rule can solve complex calculations but CANNOT do simple arithmetic. A rare and unusual exception is the newest addition to the collection - a System Korte slide rule that CAN add and subtract!
Ace Hoffman has developed an awesome simulation of a linear, round, concentric and drum slide rule. From Ace's Homepage download a function-rich version for your phone, tablet or desktop.
Lawrence made the only known slide rule considered so vital to the WWII effort that the UK & US governments had it classified - based on research from MIT it calculated radar antenna beam patterns, beam width, gain, etc.