• 455 Martinson, Los Angeles
  • 8 (043) 567 - 89 - 30
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  • ARISTO 90107 specially commissioned model for calculating the lifespan of filament lightbulbs
  • Koch, Huxhold & Hannemann (KHH) - made the 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 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 get easily damaged and unlike modern-day calculators, they do not need batteries! Most slide rules have a pair of Log x (C/D) scales but can come in many shapes and sizes:

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

Nearly all the items online are slide rules but various slide charts, novel calculating aids, a hybrid or two and even the odd electronic calculator also feature. For fledgling or existing slide rule collectors the Reference Manual published by the Oughtred Society succinctly covers the basics and much more. Or try An Easy Introduction to the Slide Rule by Isaac Asimov (yes, the SF writer). However, for cleaning/restoration tips Eric Marcotte’s or Tom Dilatush’s webpages have good ideas and helpful tips.

The slide rules in my collection come from many makers. The niche sections are my ♫ acoustic ♫ (yes, they exist!) and my oversized desktop slide rules but I also look out for models with a quirky use - e.g. for Church bells. These days I primarily focus on adding models from the Dutch slide rule makers: ALRO and Systeem Matthijssen. The entire collection has grown to 2000+ slide rules, 200+ slide charts, 40+ Ready Reckoners, 15+ slide adders, 30+ mechanical calculators and a handful of electric calculators. Every month or so I try to add a new batch - so far, roughly two-thirds of the collection is uploaded. 

Do try one of the adjacent SEARCH options or the BROWSE ALL function to see items of interest.

My wish list

wishlist
Sought after models still missing from the collection:
MakerModel(s)
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, 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
Inglisany FLASH RECKONER
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, TR, T150, T300, O2 Calculator, 30 TxC & 75 Terminator
LOGAREX27705
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 1562 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)

MakerModelType
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)10 R (AC-1.45a)Waistcoat Rietz two-tone
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)400 D (AC-1.09)Darmstadt two-tone
ALRO (All-Round)500 N (AC-1.11)Basic two-tone
ALRO (All-Round)600 E (AC-1.19)Electro
ALRO (All-Round)GEVAERT (AC-8.07)Photography
ALRO (All-Round)KLOOS (AC-1.30)Steel Constructions
ALRO (All-Round)MILITAIRE REKENSCHIJF (AC-1.32)Military Terrain Analysis two-tone
ALRO (All-Round)MILITARY CALCULATOR (AC-1.nn)Military Terrain Analysis two-tone
ALRO (All-Round)PHILIPS DATA SYSTEMS (AC-3.11)Desktop Memory Mapping 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)SHELL VISCOKLOK (AC-1.40)Petroleum
ALRO (All-Round)ST 9-430/2 (AC-1.34a)Military Artillery Range Finding (1 of 2)
ALRO (All-Round)SYNRES (AC-2.23)Desktop Paint Viscosity/Conversion
Aristo803 MonoRietzPocket Rietz two-tone
Blundell Brothers/Rules Ltd. (BRL)G.2Enhanced Mannheim without Trig scales
Blundell Brothers/Rules Ltd. (BRL)L.4Log-Log
Blundell Harling Ltd. (BH)500Academy Log-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
Hemmi260Log-Log
KingsonPocket CalculatorPocket Slide Adder
Nestler0210Darmstadt
Nestler0320Petroleum two-tone - System Dr. Schmeling
Nestler0370Electro
Nestler11 (narrow)Pocket Enhanced Mannheim
Nestler3Mannheim
Nestler37Electro - early
Nestler9Rietz
NestlerABLMilitary Vehicle Logistics & Supply
Pickett & EckelN600-ESPocket Log-Log
RUYI (Si Da Rule Factory)1083Log-Log Hyperbolic
UnknownForcing DiscHorticulture