This non-commercial website was a novel 60th birthday present from Ros. But the site 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When the latest PC/tablet is out-of-date in 6 months it may come as a surprise that the Englishman in the image, the Rev. William Oughtred (1575-1660), invented a calculator around 1621 that would be in continual daily use for nigh on the next 400 years. My hobby is collecting and writing about this analogue calculating wonder - the SLIDE RULE. The analogue concept behind the slide rule was successfully adopted and adapted by many trades and professions. Being able to use one is still a licensing condition private and commercial pilots have to meet.
This site is a virtual “display cabinet” for my collection (as it gets uploaded) of slide rules and the odd mechanical calculating aid plus a “bookshelf” for my published articles - enjoy browsing.
Anyone needing a “memory jogger” or is just intrigued how such analogue calculators of the past worked, the International Slide Rule Museum has a richly illustrated “How To Use The Slide Rule” teach yourself course or download a self-running introduction course with synchronised audio I digitalised. Afterwards try out some test calculations with Derek Ross’ online simulation of a Pickett N909-ES slide rule. If all this gets you thinking about starting your own collection then the UKSRC/OS “Beginner’s Guide to Collecting Slide Rules” can be a great help.
For any educators looking for maths related inspiration & teaching aids/material then you need to look no further than Nicola Marras’ website. But if you are just looking for reference books/publications on slide rules try one of these: List 1 or List 2.
Did you know special models exist for each of the 4 Houses of Hogwarts? Depending on your Gryffindor, Ravenclaw, Hufflepuff or Slytherin affiliations select your Harry Potter slide rule simulation from Robert Wolf’s website ...
Dutch maker All-Round, better known as ALRO, was the brainchild of C.J. Dussel & W. Pasveer. ALRO is best known for its unique and patented circular slide rules where the lid doubles up as a handy desk stand. The heyday years were 1945 to 1960 but they reinvented themselves in the early 70’s and produced many plastic slide charts & cards. Check out my many ALRO’s here ...
The US was the host of the 2020 International Meeting. Sadly the COVID-19 pandemic meant it had to be cancelled. So instead the organisers will host two 3-hour virtual IM2020 sessions in September. Everyone is welcome - the dates & all the details can found on the Oughtred Society website ….
A milestone I expected to reach earlier. It takes ages to catalogue & capture conscientiously all the details. The upside is that I am learning a lot about my collection! The1000th entry was fittingly an unusual & extremely rare KLOOS disc for heavy-duty steel constructions
As a labour of love Otto van Poelje, an expert on ALRO, has published: The ALRO Catalogue. Dutch maker ALRO is famous for circular models where the lid doubles up as a desk stand. In 200+ pages every calculating disc, slide rule & slide chart ever made by ALRO is meticulously catalogued & photographed in a hardback book. Attractively priced at Euro 35 (excl. P&P) order your copy online here ...
Rodger Shepherd sadly passed away peacefully at home on 16th April 2020. With Bob Otnes (1932-2019) Rodger co-founded the Oughtred Society (OS) in 1991. In 1992 he was the first OS Award winner and promoted publishing the Journal of the OS (JOS). He set high standards for his own research and others who subsequently published in the JOS. He translated Dieter von Jezierski’s ground-breaking 2000 book: “Slide Rules – A Journey Through Three Centuries”. Only last year he helped me make sense of a rare medical based slide rule. He will be missed.
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.
|A.W. Faber-Castell||4/92, 8/13, 8/14, 8/15, 8/168 & 51/88|
|Albert Martz||Cursor for pocket System Frank|
|ALRO||Cobol Analyser, HaTex & Truck Tyres|
|Ausschuss fuer Wirtschaftliche Fertigung (AWF)||SR703, SR705-709, & SR754|
|Controller Calculator KG||200 R|
|DARGUE Bros. Ltd / Simplon||Sub-Ivory SR-1 & SR-4 + Honduras SD10, WR-2A, WR-5 & WR-7|
|Engineering Instruments Inc.||Either circular “vinylite” model|
|Fearns Calculators||Barber Shop Harmony Calculator|
|Fowler||Nautical, Artillery, Kearns & Mackay|
|Inglis||FLASH RECKONER: Pricing, Photographic Exposure, Stock Exchange, Foreign Money, Paper Trades & Health Insurance|
|L&C Hardtmuth / Classic||10" Series III|
|Lawrence Engineering Services||S-M (C.V. Ore) & Exposure (MIT)|
|LOGA||TF, T150, T300, O2, Terminator & Baumaan lighting|
|Nestler||Cursor/runner for 24b (100cm), RP 75, Kreisrechner & Disc-O-Lator|
|Slide Rule & Scale Engineering Co. (S.E.&S.E.)||- any -|
|Systeem Matthijssen||- any -|
|Unique||Norman, Perfectus, Dial & Junior|