• 455 Martinson, Los Angeles
  • 8 (043) 567 - 89 - 30
  • support@email.com
  • Rare Otis King Model K - white scales on black background
  • Pocket Hexadecimal Slide Adder for Computer Programmers
  • Post 1824 Dring & Fage Alcohol Gauging Rule
  • Darnley’s Rotable Lightning Calculator/Pencil Case
  • Lawrence Antenna (classified by UK & US during WWII) for Radar Beam Pattern Detection
  • Makeba Kombinator pencil & slide rule
  • Rare Carbic-made Fischer Calculator
  • For Calculating Strength of Liquids 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: “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When the latest PC/tablet is out-of-date in 6 months it may come as a surprise that the Englishman in the image, the Rev.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.

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.

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 the place to start.

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

Latest additions


Slide Rules

Ausschuss fuer Wirtschaftliche Fertigung (AWF), SR 702, Belt Performance & Belt Speed poly-slide (2), L, Closed/solid frame, cardboard/plastic

Tech Papers

M comes after P

Skid Stick No. 57

news - So far 755 rules are loaded from my collection

10 January 2018

New Long-Scale EBook

In memory of long-scale expert Ed Chamberlain (†18-10-2017) fellow collector Otto van Poelje has reissued his out of print private 2013 publication: “LONG-SCALE SLIDE RULES in LIFE-SIZE IMAGES

14 October 2017


Prized pocket-watch slide rules are possibly the most tactile. Check out examples from renowned UK maker FOWLER and an example from when the company first started trading as Scientific Publishing.

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.

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 / SimplonSD10 Duplex & any WRn model + Sub-Ivory SR-1/3/4/6
Engineering Instruments Inc.Either circular “vinylite” model
Fearns CalculatorsBarber Shop Harmony Calculator
FowlerNautical, Twelve-Ten, Kearns & Mackay
Graphoplex6245 & 6250
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 & Scale Engineering Co. (S.E.&S.E.)- any -
UniqueNorman, Perfectus, Dial, Pioneer Long Scale & Junior