• 455 Martinson, Los Angeles
  • 8 (043) 567 - 89 - 30
  • support@email.com
  • Koch, Huxhold & Hannemann (KHH) - made surprising System Korte slide rule that does addition & subtraction
  • Smallwood Folding Shoe Sizing Stick in metric for French shoe sizes 10-48 in increments of a Paris point (⅔ cm)
  • Lawrence MIT Antenna slide rule for radar antenna performance was classified during WWII by UK & US governments
  • ALRO-made ruler unusually with a cursor for analysing ECG printouts of the cardiac Sinus Rhythms
  • Hatters Gauge - for measuring the size of a hat but unusually calibrated in metric & imperial
  • Glovers Rule - for measuring the length of a glove in imperial inches
  • Unusual non-logarithmic QR 41 military model by Dennert & Pape (D&P) for training anti-aircraft gunners
  • Colour combinations slide rule made by German WH-Wohnen for Interior Designers
  • Professor Fuller’s Drum Calculator from 1878 - made by W.F. Stanley
  • Modern wristwatch with slide rule bezel calculator made by German maker Kienzle
  • Ruxton made Multi-Vider combined 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 calculating aid
  • Makeba made Kombinator combination pencil & slide rule
  • Rare Carbic-made Fischer Calculator slide rule
  • Specialist slide rule for a national home cable radio broadcasting system offered in The Netherlands from 1930 to1970
  • Smallest drum (≈ 2.4m) made by renowned Swiss maker LOGA

My collection ....

In 1991, when unpacking a removal box, I came across the long-forgotten slide rule from my student days. I was intrigued - when did they become obsolete? Soon after a bizarre tongue-in-cheek idea struck me: “What else could an (ex)computer man collect but analogue slide rules!”

Slide rules do not wear out or break when dropped and unlike modern-day calculators, they do not need batteries! True slide rules have a pair of Log x (C/D) scales and they come in many shapes and sizes but most are either:

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

Most items in my collection fit this definition but various slide charts, the odd novel calculating aid and some hybrids have sneaked in. For fledgling or existing collectors the Reference Manual by the Oughtred Society covers all the basics and much more. Or else try An Easy Introduction to the Slide Rule by Isaac Asimov (yes, the SF writer). But if you just need cleaning/restoration tips Eric Marcotte’s or Tom Dilatush’s webpages can help.

My collection includes items from many makers. The niche sections are my ♫ acoustic ♫ (yes, they exist!) and my oversized desktop slide rules or ones with a quirky use - e.g. for Church bells. . Nowadays I also specialise in models from the only two Dutch slide rule makers: ALRO and Systeem Matthijssen. The collection has grown to 2000+ slide rules, 200+ slide charts, 40+ Ready Reckoners, 15+ slide adders and 30+ mechanical calculators. Every month or so I add a new batch of items but it will be ages before the entire collection is uploaded! 

Do try one of the adjacent search options or the browse all function to find items of interest.

My wish list

Sought after models still missing from the collection:
A.W. Faber-Castell1/38, 8/13, 8/14, 8/15, 20/44/3 & 51/88
Addiator GmbHOctadat
AHREND (Wed. J. Ahrend & Zoon)649, 651, 696, 698, 699 & 701
ALRO (All-Round)101, 10 RL, Beton, Cycloop, GoA, Ha.C/P/Q/V, Ha TEX, Piret, Philips Calendar, Nomographie, Van Leer, Vonderlingenplaat & WeR4
AWF (Ausschuss fuer Wirtschaftliche Fertigung)SR703, SR705-709, & SR754
Controller Calculator200 R
DARGUE Bros. Ltd. / SimplonSub-Ivory SR-1 & SR-4 + Honduras SD10, WR-2A, WR-5 & WR-7
Fearns CalculatorsBarber Shop Harmony Calculator
FowlerNautical, Artillery, Kearns & Mackay
ITAB (Internationaler Tabellenverlag)Multicalor Flachheizkorper & Styropor-Vollwarmeschutz
IWA (Ingenieurbuero fuer wirtschaftliches Arbeiten)15489 Harmonik
Johann Faber180/080, 180/082, 9201, 9202, 9203 & 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)
LOGA Calculator A.G.TF, T150, T300, O2 Calculator, 30 TxC & 75 Terminator
Logomat Rechengeräte1300/1303
NestlerRP 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 1471 items so far uploaded from my collection

Note: given the large number of items the list can take a minute or two to build.

Unusual Slide rules for sale or swop (click on the 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-Castell62/83Pocket Technical/Log-Log long-scale
Addiator GmbHARITHMAPocket Slide Adder - silver
Addiator GmbHDUPLEXSlide Adder - silver
AHREND (Wed. J. Ahrend & Zoon)642TRietz
ALRO (All-Round)100 R (AC-1.04a)Rietz - H
ALRO (All-Round)100 R (AC-1.04b)Rietz - early
ALRO (All-Round)1010 Commercial (AC-1.18)Business long-scale
ALRO (All-Round)200 R (AC-1.05a)Rietz - two-tone paper discs
ALRO (All-Round)200 RL (AC-1.49a)Rietz
ALRO (All-Round)300 D (AC-1.08a)Darmstadt
ALRO (All-Round)600 E (AC-1.19)Electro
ALRO (All-Round)746 De Muiderkring (AC-1.nn)Waistcoat Radio Electronics
ALRO (All-Round)KLOOS (AC-1.30)Steel Constructions
ALRO (All-Round)MILITAIRE REKENSCHIJF (AC-1.32)Military Terrain Analysis
ALRO (All-Round)MILITARY CALCULATOR (AC-1.nn)Military Terrain Analysis
ALRO (All-Round)PHILIPS DATA SYSTEMS (AC-3.11)Desktop Electronics for computer programmers
ALRO (All-Round)PLANISFEER (AC-6.05)Desktop Astronomy - Northern Hemisphere
ALRO (All-Round)PTT DECIBEL (AC-1.42)Radio Electronics
ALRO (All-Round)PTT DECIBEL (AC-1.43)Pocket Radio Electronics
ALRO (All-Round)SHELL VISCOKLOK (AC-1.40)Petroleum
ALRO (All-Round)ST 9-430/2 (AC-1.34a)Military Artillery Range Finding (1 of 2)
Blundell Brothers/Rules Ltd. (BRL)G.2Enhanced Mannheim without Trig scales
Blundell Brothers/Rules Ltd. (BRL)L.4Log-Log
CONCISE (K.K. Konsaisu)28Pocket Enhanced Mannheim without Trig scales
CONCISE (K.K. Konsaisu)CTCS-552Pocket Chemical
Dennert & Pape (D&P)D 2/28Enhanced Mannheim - early
Dennert & Pape (D&P)S 6/28 (System Rietz)Rietz
DIWA (Dansk Industri Waterpas A/S )1-1 Rietz-IdealRietz
DIWA (Dansk Industri Waterpas A/S )201 Technical (ver.1) Rietz
ECOBRA (Bayerische Reisszeugfabrik)1461Pocket Rietz
Graphoplex620 d (ver. 1)Rietz
Graphoplex630Geometre Stadia Topography - 400g early
Graphoplex640Electro Log-Log
Heath & Co.Hezzanith Le PatourelCelestial Navigation/Mannheim
Hemmi135Pocket Darmstadt
Hemmi255DElectro Hyperbolic
KingsonPocket CalculatorPocket Slide Adder
Nestler0320Petroleum two-tone - System Dr. Schmeling
Nestler11 (narrow)Pocket Enhanced Mannheim
Nestler37Electro - early
NestlerABLMilitary Vehicle Logistics & Supply
RUYI (Si Da Rule Factory)1083Log-Log Hyperbolic