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 F-C Laukhuff Organ Pipes/System-Rensch

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When the latest PC/tablet is out-of-date in 6 months it may come as a surprise that the Englishman in the image, the Rev.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 “display cabinet” for my collection (as it gets uploaded) and a “bookshelf” for my stories - enjoy browsing.

News - So far 597 rules are loaded from my collection

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

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 ?

02 November 2016

NEWLY LOADED – the highlights

Added in recent weeks: (i) latest two articles to be published, (ii) a rare hybrid model, (iii) a “lost” Bakelite model and (iv) an unusual large circular model for typography.

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.

07 February 2014


Site totally revamped/restyled to take advantage of modern design features & navigation aids.

Please tell me what you think ....

Latest additions

Slide Rules

Orgelbau-Fachverlag, Scaling Organ Pipes, Desktop Music - System Rensch, L, Closed frame, thin plastic

Tech Papers

Wrong Way Up !

Gazette Colin Barnes Memorial Issue 2016

The history - How it all began ....

To learn more about the history of this remarkable calculating wonder check out the Oughtred SocietySlide Rule History” 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. After that try doing a few trial calculations with Derek Ross’ online simulation of a Pickett N909-ES slide rule.

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 .

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 and 8/168
Blundell Harling Ltd. (BH)P4463 Holophane Illuminance Calculator
Dargue Brothers Ltd / SimplonSimplon SD10 Duplex
Engineering Instruments Inc.Either “vinylite” circular models
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 / ClassicPoclet 5" Series II & 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