• 455 Martinson, Los Angeles
  • 8 (043) 567 - 89 - 30
  • support@email.com
  • Unusual non-logarithmic squaring desktop QR 41 model by Dennert & Pape (D&P)
  • Colour combinations slide rule for Interior Designers
  • Professor Fuller’s Drum Calculator from 1878 - made by W.F. Stanley
  • Modern Kienzle wristwatch with slide rule bezel calculator
  • Ruxton Multi-Vider drop-lead pencil & slide rule
  • Rare Otis King Model N for Retail & Monetary with white scales (422 & 424) on a black background
  • Darnley’s Rotable Lightning Calculator/Pencil Case
  • Design for this Antenna Radar Beam Pattern Detection slide rule was classified during WWII by UK & US governments - made by Lawrence
  • Makeba Kombinator pencil & slide rule
  • Rare Carbic-made Fischer Calculator
  • Specialist slide rule for a national home cable radio broadcasting system offered in The Netherlands in the 1900s
  • Smallest drum (≈ 2.4m) made by LOGA

My collection ....

In 1991, while unpacking a removal box, I came across the long-forgotten slide rule from my schooldays. I was intrigued by its history and soon a tongue-in-cheek idea was born: “What else could a computer man collect but analogue slide rules!”

Slide rules come in all shapes and sizes but most are either:

  • Linear - by far the most common
  • Circular or disc
  • Drum or cylinder
  • Tubular
  • Watch (pocket or wristwatch)

They are hard wearing, do not break when dropped and unlike modern day calculators they do not need batteries! Strictly speaking to be a slide rule it must have at least a pair of logarithmic scales. Most items in my collection fit this definition but the odd novel calculating aid and some hybrids have sneaked in!

For enthusiasts or fledgling collectors/users there is an excellent online Reference Manual by the Oughtred Society covering all the basics and much more. Alternatively try An Easy Introduction to the Slide Rule by Isaac Asimov (yes, the SF writer). For cleaning/restoration tips try Eric Marcotte’s or Tom Dilatush’s webpage.

My speciality is ♫ acoustic ♫ (they exist!) and oversized desktop slide rules. But I am also intrigued by any slide rule with a quirky or innovative scale and novel applications - e.g. for Church bells. My collection has grown to 2000+ slide rules, 100+ slide charts, 40+ Ready Reckoners, 15+ slide or dial adders and 30-odd mechanical calculating machines/aids. To find specific items of possible interest try one of the adjacent search options.

Every month or so a new batch is added but because of the sheer volume involved it will take many months, if not years, before the entire collection is uploaded! So check out the relevant NEWS item on the HOME page to see what was in the latest batch!

My wish list

Sought after slide rules still missing from the collection:
A.W. Faber-Castell8/13, 8/14, 8/15 & 51/88
Addiator GmbHOctadat
AHREND (Wed. J. Ahrend & Zoon)642T, 649, 651, 690, 696, 698, 699 & 701
Albert MartzCursor for pocket System Frank
AWF (Ausschuss fuer Wirtschaftliche Fertigung)SR703, SR705-709, & SR754
DARGUE Bros. Ltd. / SimplonSub-Ivory SR-1 & SR-4 + Honduras SD10, WR-2A, WR-5 & WR-7
Engineering Instruments Inc.Either circular “vinylite” model
Fearns CalculatorsBarber Shop Harmony Calculator
FowlerNautical, Artillery, Kearns & Mackay
ITAB (Internationaler Tabellenverlag)Multicalor Flachheizkorper & Styropor-Vollwarmeschutz
IWA – F. Riehle GmbH & Co KG15489 Harmonik
Johann Faber180/080, 180/082, 9203, 9204 & 9204
Keuffel & Esser (K&E)4081-3 Braille version
KOSMOSBook: "De Rekenliniaal" - 11th & 12th Editions
L&C Hardtmuth / Classic10" Series III
Lawrence Engineering ServicesS-M (C.V. Ore) & Exposure (MIT)
LOGATF, T150, T300, O2, Terminator & Baumaan lighting
NestlerCursor/runner for 24b (100cm), RP 75, Kreisrechner & Disc-O-Lator
S.R.&S.E. (Slide Rule & Scale Eng. Co.)- any -
Systeem Matthijssen- any -
UniqueJunior, Study 500/700/900 & J180/181/182

Search by maker

Search by keyword

Tip: separate keywords (implict AND) by a space or a comma and if needed, limit the search by adding keywords proceeded by a hyphen: e.g.-Faber, -plastic. Phrases in quotes may also be used.

Browse all 1209 slide rules so far loaded from my collection

Note: given the number now uploaded this page can take several minutes to load.

Unusual Slide rules for sale or swop (click on model for details)

A.W. Faber-Castell111/22Business
A.W. Faber-Castell2/82Technical/Log-Log
A.W. Faber-Castell2/83Technical/Log-Log long-scale
A.W. Faber-Castell2/83NTechnical/Log-Log long-scale
A.W. Faber-Castell378Electro
A.W. Faber-Castell62/83Pocket Technical/Log-Log long-scale
AHREND (Wed. J. Ahrend & Zoon)ELECTRO 15Electro
AHREND (Wed. J. Ahrend & Zoon)HOLLANDIA-REKENSTOKEnhanced Mannheim
ALRO (All-Round)200 R (AC-1.05a)Rietz
ALRO (All-Round)200 RL (AC-1.49)Rietz
Blundell Brothers/Rules Ltd. (BRL)G.2Enhanced Mannheim without Trig scales
Blundell Brothers/Rules Ltd. (BRL)L.4Log-Log
Dennert & Pape (D&P)D 2/28Enhanced Mannheim - early
Dennert & Pape (D&P)S 6/28 (System Rietz)Rietz
ECOBRA (Bayerische Reisszeugfabrik)1461Pocket Rietz
Graphoplex1614School Log-Log C.A.P.
Graphoplex16ooSchool Riez C.A.P. - early & all black
Graphoplex620 d (ver. 1)Rietz
Graphoplex630Geometre Surveying Topography - 400g early
Graphoplex640Electro Log-Log
Heath & Co.HezzanithNavigational Mannheim
Hemmi135Pocket Darmstadt
Hemmi255DElectro Hyperbolic
Nestler0137Pocket Electro two-tone
Nestler11Pocket Enhanced Mannheim
Nestler43Reinforced Concrete - System Hoffmann
NestlerABLMilitary Vehicle Logistics & Supply
NORMA-MechanikMekuria 190Business
William LangleyCarpenter TimberDesktop Coggeshall