• 455 Martinson, Los Angeles
  • 8 (043) 567 - 89 - 30
  • support@email.com
  • Pocket Octal/Hexadecimal calculator for computer programmers
  • Mystery Dennert & Pape Desktop “Quadrat-Rechenscheiber”
  • Post 1824 Dring & Fage Gauging Rule
  • Darnley’s Rotable Lightning Calculator/Pencil Case
  • Lawrence Antenna (classified in WWII)
  • Makeba Kombinator pencil & slide rule
  • Rare Carbic-made Fischer Calculator
  • For calculating in Twaddells !!
  • PTT rule for Cable Radio (Signal Loss/dB)
  • Smallest drum (≈ 2.4m) made by LOGA

A man must have a hobby….


This non-commercial website was a 60th birthday present from Ros. The name stems from another family member - our daughter Siân. As a teenager she often told her friends: “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When the latest PC/tablet is out-of-date in 6 months it may come as a surprise that the Englishman in the image, the Rev.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.

This site is a virtual “display cabinet” for my collection (as it gets uploaded) of
slide rules and the odd calculating aid plus a “bookshelf” for my published articles - enjoy browsing.

The history - how it all began ....


To learn more about the history of this remarkable calculating wonder check out the “Slide Rule History” by the Oughtred Society or my 2-page summary (in Dutch!).

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 …” guide. Afterwards try doing a few trial calculations with Derek Ross’ online simulation of a Pickett N909-ES slide rule. Thinking of starting your own collection? Then the Oughtred Society’s Beginner’s Guide to Collecting Slide Rules is a great place to start.

Educators looking for related inspiration & teaching aids/material need look no further than Nicola Marras’ website. But if just looking for reference books try one of these: MyList 1 or MyList 2 .

Latest additions


Slide Rules

J.H. Steward Ltd., Motor Transport, Military Vehicle Logistics & Supply, L, Duplex, wood/plastic verneers

Tech Papers

Wrong Way Up !

Gazette Colin Barnes Memorial Issue 2016

news - So far 682 rules are loaded from my collection

03 July 2017

LATEST ADDITIONS - the highlights

Big Beasts*” or desktop models are a speciality of my collection. Most leading makers had them but they were <5% of the sales volume – so they are rare.
Check out here the 80 odd recently uploaded.

* so called because for the rectilinear ones (40/50/60/100 cm) you need arms like an Orang-utan to use them!

11 March 2017


Site remodelled & restyled to make it “technology neutral”. It should display optimally on any type of h/w device (incl. tablets & smartphones) or browser. Also the restyled search options work faster & more intuitive.

Please tell me what you think ....

02 February 2017


Recently uploaded, the only slide rule conceived so vital to the WWII effort that the UK & US governments had it classified.

25 January 2017

Unexpected Post!

Many thanks to whoever anonymously sent me a pocket ”SpeedyReady Reckoner from the UK (postmarked: South Midlands).

17 January 2017

A New Year, new opportunities

Rod Lovett’s search engines are unmissable tools. Have you tried the two new options added late last year: (i) Long Scale Rules & (ii) Hyperbolic Archive ?

28 October 2016

Have I Got News For You!

The UKSRC Slide Rule Gazette was the guest publication on British television’s highly acclaimed weekly satirical comical news quizz HIGNFY - see the You Tube clip.

21 September 2016

IM2016 - “Splendido!”

The International Meeting in Trento, Italy was memorable - download all the Papers or watch the presentations.

The IM2017 will be held in Germany.

Bis September in Bonn.

My wish list

Sought after slide rules still missing from the collection:
A.W. Faber-Castell4/60, 4/92, 8/13, 8/14, 8/15 & 8/168
Addiator GmbHOctadat
AlroCobol Analyser, Ha Tex & Truck Tyres
Blundell Harling Ltd. (BH)P4463 Holophane Illuminance Calculator
Dargue Brothers Ltd / SimplonSimplon SD10 Duplex + sub-ivory models
Engineering Instruments Inc.Either circular “vinylite” model
Fearns CalculatorsBarber Shop Harmony Calculator
Festus Mfg. Co. / Acu-Rule Mfg. Co.100
InglisFLASH: Pricing, Photographic Exposure, Stock Exchange, Foreign Money, Paper Trades & Health Insurance
IWA15489 Harmonik
L&C Hardtmuth / Classic10" Series III
Lawrence Engineering ServicesS-M (C.V. Ore) & Exposure (MIT)
NestlerCursor (runner) for 342 (50cm) & 24b (100cm)
Slide Rule and Scale Engineering Co.- any -
UniqueNorman, Perfectus, Dial, Pioneer Long Scale & Junior