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  • 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

All papers - click on/select any of the download options to see the paper

Currently there are 56 slide rule related articles to choose from. To narrow down the choice, go to the search papers page.

MagazinePublisheddownload
M comes after P
Skid Stick No. 57 October 2017 download

UK maker Blundell Harling (BH) was with over 5000 models, the champion producer of specially commissioned slide rules. But not all of them were BH branded. Help in identifying such unbranded but HM-made slide rules came in 2000 when a list of P Numbers showing the serial numbers of such commissions was published. In 2017 it came to light that some unbranded models can also carry a M Number (n.b. co-authored with Peter Soole).

[Blundell] [Unbranded]

Overlooked Beauties
Proceedings IM2017 September 2017 download

Slide rule collectors are always looking out for a lost gem or the big find. More than often all we ever find is another cardboard or cheap plastic slide rule with just a few logarithmic scales. But some of these simple & everyday looking “ugly ducklings” can, like in the Hans Christian Andersen fairy tale, turn out to be amazing “swans”. This compilation (descriptions & images) features many such often overlooked beauties divided over 12 themed galleries (n.b. co-authored with some members of the German RST collectors group).

[Health & Medical] [Money] [Merchants] [Food & Beverages] [Construction & Home Improvement] [Heating] [Arears & Volumes] [Calendar] [Cars] [Speed] [Photography] [All-in-One]

Wrong Way Up !
Gazette Colin Barnes Memorial Issue 2016 October 2016 download

Surprisingly right up to the 1960s “how to use a slide rule” sessions were not taught in secondary schools. In fact in most countries no course on calculating with a slide rule ever became part of their national school curriculum.

[35mm] [carousel] [demonstration] [dia] [education] [Faber-Castel] [multimedia] [OHP] [projector] [teaching] [Thornton] [training]

The Lost Scales of Unknown Riches (last updated: January 2017)
Proceedings IM2016 & Gazette Colin Barnes Memorial Issue 2016 September 2016 download

Your eyes can deceive you, don’t trust them. There are always exceptions and sometimes we only see what we want to see.

[British] [efficiency] [electrical] [English Electric] [Lilliput] [Obi-Wan] [PF] [Power Factor] [Riches] [Star Wars] [Thornton]

Slide Rule Hunting, opniew / Slide Rule Hunting, again
MIR No. 71 August 2016 download

Wanneer je in het buitenland op zoek voor zoiets als het lang vergeten rekenliniaal bent, kan zelfs in sommige delen van Europa een Engels vertaling of gebarentaal niet genoeg zijn. Een lijst met de inheemse spelling voor een rekenliniaal kan helpen.

When hunting for something like a “long forgotten” slide rule in other continents or even in some parts of Europe, English or hand/foot sign language is often not enough. Knowing the native spelling can help.

[Dutch] [foreign] [translate] [translation]

Kunstzinnige verdeeling / Artistic divisions
MIR No. 70 March 2016 download
Iedere verzamelaar van rekeninstrumenten heeft vanzelfsprekend enige affiniteit met rekenen. De klassieke en bijzondere Gulden Snee verhouding φ = 1,618 (ofwel phi) is de basis voor een speciaal in opdracht gemaakt installatie ik heb om mijn tuin te verfraaien.

Every collector of calculating devices has a certain affinity with mathematics and calculating. The classic and extraordinary “Golden

Ratio” (φ = 1,618) is the basis for the specially commissioned installation I have in my garden.

[Dutch] [sculpture]

Een 400 jaar oud rekenwonder / 400-year old calculating wonder (interview by Kees den Elzen)
Aschpotter no.37 November 2015 download

Bij ‘vroeger’ denken we meestal eerst aan de geschiedenis van landen, van mensen, van dorpen. Maar vroeger werden ook gewone dingen heel anders gedaan dan nu het geval is.

When thinking about the past we usually start with the history of countries, of people and of villages. But in such bygone days many everyday activities were done very differently than today.

[ALRO] [bulbs] [forcing] [Dutch] [History] [Mannheim] [Muiderkring] [Oughtred] [radio] [Sassenheim] [SOS]

Yellow   +  Blue … approximately Green
Gazette Issue 16 & MIR No. 70 (March 2016) September 2015 download

Remarkably the basic design of the slide rule has lent itself to many unlikely trades and professions – usually through innovative scales but for one all the scales are just swatches of colour!

[chromatic] [color] [saturated] [slider] [unsaturated] [WK-Farbschieber] [WK-Wohnen]

Corpulent Governance
Gazette Issue 16 September 2015 download

A regime of eating habits, philosophies and practices by which body fat is managed and controlled.

[Anthropometry] [BMI] [calculator] [health] [obesity] [tape measure] [Waist-to-Hip]

Graphic Log Tables: A Picture Should Have Been Worth A Million Numbers!! (last updated: Feb. 2016)
Proceedings IM2014 & MIR No. 71 (August 2016) September 2014 download

Given what they replaced it feels disparaging, impolite and almost blasphemous to point out that logarithmic tables were sadly error prone and irritatingly awkward to use. Surely graphic logarithmic tables must have been the answer! Paradoxically they did not but they did have an unexpected link to certain models of slide rules.

[Addiator] [Faber-Castell] [Haro ] [Kienbaum] [Koch] [Kubler] [Lacroix] [Lalanne] [Leder] [Loewe] [logs] [Maximator] [Napier] [nomogram] [Obbink] [Pressler] [Putschbach] [Ragot] [Rohrberg] [Tichy]

Mystery Casella Desktop
Proceedings IM2014 September 2014 download

A description of a mystery L.P. Casella. wooden desktop “one-off” slide rule (made with no cursor) from the 1930s with various inexplicable scales, many of which are expanded versions for extra accuracy. All the scales appear non-standard.

[Harling}

Two Tribute Show Prototypes
Proceedings IM2014 September 2014 download

A description of Radiation Dosage Calculator for Contamination Over Land and Dark-Room Exposure Time Calculator show prototypes.These stainless-steel calculators, professionally made to the highest standards, were “specially commissioned” by a Dutch engineer, Dr. Ir. Ing. J.W. van Beek, in the 1970s. He had them made so that they could become lasting tributes to the much-loved originals he had personally used.

[BRL] [Orr] [TUD]

Mystery Thornton Desktop
Proceedings IM2014 September 2014 download

A description of a mystery A.G. Thornton Ltd. desktop “one-off” slide rule from the late 1950s/early 1960s - possibly an unfinished factory prototype as there seems no good reason for either the scale layout or for it being the size it is!

New Exhibition Opens: “The Schuitema Collection”
JOS Vol. 23 No.1 April 2014 download

Fate can sometimes be cruel. Sadly, after a long illness, renowned “champion” Dutch collector and author IJzebrand Schuitema (1929-2013) died two months before an exhibition dedicated to his famous collection opened at the Arithmeum Museum in Bonn, Germany.

Engineers in Tights!! - specialist slide rules for the textile industry (last updated: July 2014)
Proceedings IM2013 October 2013 download

Despite being past the heyday of the Second Industrial Revolution “engineers in tights” made sure slide rule innovation persisted well into its twilight years.

[57/74] [ARISTO] [Blundell] [denier] [Faber-Castell] [LOGA] [Nestler] [Schirdewan] [Seehase] [System]

Graphic Logarithmic Tables: A Picture Is Worth A Million … Numbers
Collectanea de Logarithmis (DVD) September 2013 download

Given what they replaced it seems disparaging, impolite and almost blasphemous to point out that logarithmic tables were sadly error prone and irritatingly awkward to use!

[Kienbaum] [Koch] [Kubler] [Lacroix] [Leder] [Loewe] [logs] [Napier] [nomogram] [Obbink] [Pressler] [Putschbach] [Ragot] [Rohrberg] [Tichy]

Pouch Clips V – the naked clip
Gazette Issue 14 September 2013 download

Despite discovering yet another shocking new category, the rule clip, most clips remain rare and mostly American.

[Dietzgen] [Eckel] [Faber-Castell] [Lafayette] [Pickett] [P&E] [POST]

When size matters!!
Skid Stick No. 44 June 2013 download

Collectors of slide rules are a chatty and sociable bunch – inevitably the conversation at some point turns to: “well, just how big is your collection?”

[standard] [measure] [distance] [speed]

Russian Slide Rule: size of a building!
MIR No. 60 October 2012 download

How could anything ever surpass the Texas Magnum of Skip Solberg and Jay Francis? But when it comes to the largest slide rule ever built, it has a Russian challenger - Bashkir State University!

[extra-long] [Ufa]

C.C. Moler Line Loss and Voltage Drop Calculator
Proceedings IM2012 September 2012 download

A description of a special purpose DUPA wooden poly-slide duplex slide rule for calculating the line loss and voltage drop on electrical distribution lines.

[Dennert] [D&P] [Esser] [K&E] [Keuffel] [nomogram] [transmission]

W.H. Glaser’s textile conversion rule
Proceedings IM2012 September 2012 download

A description of an early 20th century English “oversized” wooden desktop “one-off” slide rule (with an unusual fixed cursor) for the textile trade.

[British] [extra-long] [imperial] [poly-slide] [Rankin]

Slide Rules for Computer Programmers or .......... 53 6c 69 64 65 20 52 75 6c 65 73 20 66 6f 72 20 4
Proceedings IM2012 September 2012 download

Despite sounding weird and as challenging other visual oxymorons like “invisible ink” and “bricked-up windows” there was a time when computer programmers needed some seemingly old-fashioned calculating and conversion aids.

[Abacus] [adder] [binary] [Canon] [colour] [color] [Colossus] [Comfort] [Clopper] [Coldner] [decimalisation] [digital] [EDI] [Hexadaisy] [Hexadat] [Hexadder] [hexadecimal] [HP] [IBM] [imperial] [Kubler] [octal] [Sterling] [TI] [Turku] [UNIVAC]

George R. Stibitz’s Film Slide Rule: a computing machine with logarithmic scales
JOS Vol. 21 No. 1 April 2012 download

George R. Stibitz was special. He was a prolific inventor and won many prestigious honours and awards. He is often rightly cited as: “The father of the modern digital computer”. Sadly the military overtones associated with the Stibitz Film Slide Rule probably stopped it (and still does) getting the recognition and publicity it rightly deserved (n.b. co-authored with Dieter von Jezierski).

[Army] [NDRC]

The Unique Lawrence (last updated: February 2017)
Proceedings IM2011 and Gazette Issue 13 September 2011 download

It is easy to think that slide rule innovation and creativity in the 20th century was largely the domain of commercial greats like Nestler, Faber-Castell, Keuffel & Esser, etc. But like its maligned UK “counterpart” Unique, the ubiquitous Lawrence is wrongly and unfairly just seen as an American “pile ‘em high and sell ‘em cheap” maker of slide rules. The Lawrence legacy is undoubtedly an unsurpassed portfolio of surprisingly innovative and inventive slide rules.

[25¢] [Bozarth] [brand] [Engineering] [Indiana] [Lee] [OEM] [Peru] [Snyder] [Wabash]

LINEX balls solves mystery
MIR No. 57 September 2011 download

It happens a lot – well, it happens a lot to me. I see an intriguing slide rule or something a bit different and I think I am sure I have seen something like that before. This time a faint memory solved a mystery.

[Graphoplex] [tensioning]

Pouch Clips IV
Gazette Issue 12 August 2011 download

Despite discovering a new category, the clip rule, pouch or rule clips remain rare and mostly American.

[Baux-Arts] [concrete] [Eckel] [Faber-Castell] [Parisan] [Pickett] [P&E]

J. H. Steward : A Family Dynasty
Gazette Issue 12 August 2011 download

At the end of the 19th century an unsung and now sadly largely forgotten instrument maker and retailer had its heyday.

[ACE] [Army] [Bisley] [Bosworth] [Goble] [Goldsmith] [Hall] [M.T.] [optics] [Norden] [NRA] [RHS] [Wimbledon]

Uw Merk Is Uw Stille Verkoper! / Your Brand is your Silent Marketer!
MIR No. 54 October 2010 download

In deze tijd van het globale bereik van Internet, zijn nationale “verkoopgrenzen” of zelfs die binnen de Benelux vaak niet meer relevant of actueel. Maar er is een tijd geweest, dat de keuze van een handelsmerk of merknaam in het Nederlands een belangrijk deel van de verkoopstrategie was.

In these days of global reach through the Internet national “selling boundaries”, even within the Benelux, are often irrelevant or out-of-date. But there was a time when the choice of a trademark or brand name was a major part of any sales strategy.

[Dutch] [brand] [MERK-o-GRAAF]

MAXI Desktop Slide Rule
Proceedings IM2010 September 2010 download

A description of a Nestler 100cm desktop model 24b slide rule (n.b. description includes generic production stats, etc for desktop and demonstration slide rules).

[extra-long]

Desktop Poly-Silde Rule for Steel Bars & Sections (last updated: July 2013)
Proceedings IM2010 September 2010 download

A description of a large “one-off” slide rule designed for the imperial-based calculations prevalent in the steel trade.

[Blundell] [poly-slide]

Slide Rules for Basic Tractor Calculations (last updated: July 2013)
Proceedings IM2010 September 2010 download

A description of a “one-off” specialist agricultural slide rule/chart to calculate the pulling power of a tractor.

[agricultural] [engine] [husbandry] [Hyatt]

What a load of Twaddell (last updated: July 2015)
Gazette Issue 11 August 2010 download

For most, twaddell is an outdated expression to describe some written or spoken gibberish but even if it sounds too ridiculous for words, it is also the name of a special scale for measuring the acidity or sweetness of liquids.

[alcohol] [British] [density] [hydromter] [Lovi] [Macintosh] [pottery] [SG] [slip] [strength] [tanning] [Wilson]

Undaunted and Still As Rare As A ..... Pouch Clip !
Gazette Issue 11 August 2010 download

Why yet another update? One of Andy Warhol’s (1928-1987) more famous quotes is: “... everyone will be famous for 15 minutes.” It seems my 15 minutes of fame may come from pouch clips!

[ARISTO] [DIETZGEN] [ECOBRA] [Faber-Castell]

The Mystery of the Disappearing Bakelite (last updated: October 2016)
JOS Vol. 19 No. 1 April 2010 download

Surely a wooden slide rule must be more tactile than one made of plastic? If they could talk, a fine boxwood slide rule with a rich patina must have “lived” more and have more stories to tell than any plastic contemporary. The one exception to the rule should have been an all-Bakelite slide rule but after showing great promise as a raw material the Bakelite process turned out to be fatally flawed.

[angle] [Baekeland] [Blundell] [brand] [BRL] [enamalled] Hammelburger] [Holophane] [illumination] [tensioning]

Reckon on it! A very British trait (last updated: January 2017)
Proceedings IM2009 September 2009 download

As soon as currencies were established, bartering fell out of fashion and multiplication skills were needed to succeed in business. However, for over a century the calculating aid of choice for trade and commerce was the Ready Reckoner and not the slide rule.

[Addiator] [bareme] [Blundell] [deciimalisation] [Faber-Castell] [Fenning] [Flash] [Gall] [HABS] [hybrids] [imperial] [Inglis] [Metric] [Nestler] [Robson] [Reckoner] [tables] [Unique]

Croquet anyone ???
Gazette Issue 10 August 2009 download

I have often followed a promising URL only to end up down a “blind alley”. But you can also stumble upon little gems – like the Croquet Circular Slide Rule.

[handicap] [Nels] [Plummer] [step-calculator] [unisex] [Wimbledon]

Mind the Edge (last updated: August 2013)
Skid Stick No. 32 June 2009 download

A slide rule can stay on my desk for weeks. Mostly it just needs cataloguing or filing away but on occasions it is because something about it is … well “odd”. This time my curiosity was prickled by an uncommon pre-1930 double bevelled-edged Faber-Castell model 361 slide rule from their 3xx series.

Slide Rule for Colour Mixing/Sampling?
Proceedings IM2008 September 2008 download

A description of a mystery “one-off” slide rule with bands of colour rather than scales. Possibly some kind of colour mixing aid.

[color] [poly-slide] [sampling]

Slide Rule for Signal/Power Loss
Proceedings IM2008 September 2008 download

A description of an unusually designed “one-off” slide rule of Dutch (PTT) origin. Originally thought to be for calculating the combined signal loss for a given number of telephone subscribers but at the IM2014 in Delft its true provenance of dimensioning for a Dutch cable radio (“Draadomroep”) system was presented. This subscriber based system operated from 1930s to the 1970s.

[CWP] [transmission]

Calculating for Profit
Proceedings IM2008 September 2008 download

Instead of just calculating the profit, a specialist slide rule for heating oil developed by Shell (SNV) was the reason for the profit and the greatly increased Shell’s market share!

[ARISTO] [boilers] [BP] [central-heating] [CO] [efficiency] [Faber-Castell] [Nestler] [temperature] [soot] [Unique]

Never Mind The Quality ….. Feel The Width
Gazette Issue 9 August 2008 download

The setting of a bespoke tailor’s workshop which was developed into a late 1960’s television comedy series could so easily have contained the two intriguing Tailor’s Squares which are the basis for this article (n.b. co-authored with Jenny Hutchinson).

[cutter] [Mahon] [Rabone] [ready-to-wear] [Preston] [Savile] [Vincent] [Williamson]

REED Riddle Solved!
JOS Vol. 17 No. 1 April 2008 download

Slide rules from the Southern Hemisphere are mostly unknown, scarce and one in particular, shrouded in mystery.

[Australia] [AWA] [D/L] [electronic] [Faber-Castell] [Home] [Nagaoka] [Service] [Sydney]

Een 400 jaar oud rekenwonder en Shell / A 400-year old calculating wonder and Shell
VOEKS nieuws (magazine for retired personel of the Royal Dutch Shell) September 2007 download

Het spreekwoord luidt: ”Elke zot heeft zijn marmot” of iedereen heeft wel een hobby. Voor velen is het ideaal wanneer je van je hobby je beroep kunt maken.

The saying goes, “Everybody needs an interest” or everyone has a hobby. For many it is ideal when you can turn your hobby into your profession.

[Dutch] [Gunter] [Mannheim] [Napier] [Oughtred]

Slide Rule for Imperial Units
Proceedings IM2007 September 2007 download

A description of a “one-off” mystery desktop slide rule with logarithmic scales for imperial units.

[British] [timber]

2-set Slide Rule for Reinforced Concrete & Reinforced Concrete Beams - “Michaelis Sectors”
Proceedings IM2007 September 2007 download

A pair of “one-off” specialist slide rules for calculating the desired mix for reinforced concrete.

2-set Slide Rule for the Oil Industry
Proceedings IM2007 September 2007 download

A pair of “one-off” slide rules for oil industry related calculations by Gasiorowski.

[BP] [chemical] [nomogram]

Still As Rare As A ..... Pouch Clip!
Gazette Issue 8 August 2007 download

Despite finding a few new examples, pouch clips remain rare and mostly American.

[brand] [Eckel] [Escher] Keuffel] [K&E] [Pickett] [P&E] [POST] [UTO]

Rekenliniaal Wint Marktaandeel / Slide Rule Wins Market Share
MIR No. 44 April 2007 download

In plaats van slechts de winst uit te rekenen, een specialistische rekenliniaal ontwikkeld door Shell (SNV) voor olie gestookte C.V. ketels was de reden voor de winst en een aanzienlijke toename van Shell’s marktaandeel!

Instead of just calculating the profit, a specialist slide rule for heating oil developed by Shell (SNV) was the reason for the profit and the greatly increased Shell’s market share!

[boilers] [central-heating] [CO] [Dutch] [efficiency] [Faber-Castell] [temperature] [soot] N.B. prequel to extended version published later in IM2008 Proceedings

Confusing – it gets better!
Skid Stick No. 25 February 2007 download

Unlike Anthony Manville (UKSRC: SS no. 24), I cannot play an instrument. However, I like to “jazz up” and keep my collection interesting by adding related colourful attributes - like a slide rule vinyl LP.

[acoustic] [Johnson] [music] [Parlophone] [Winding]

Slide Rules Are (Still)  … Music To My Ears!
Proceedings IM2006 September 2006 download

Expanded and extended version of the the original 2005 publication but now showing how many aspects related to music are linked to mathematics, logarithms and slide rules.

[acoustic] [Blundell] [carillon] [Faber-Castell] [Fenning] [Fritsen][harpsichord] [harmonics] [IWA] [Lawrence] [Lloyd] [nomogram] [Petit] [piano] [pipes] [organ] [Rensch] [Taylor] [transposer]

Rare As A .... Pouch Clip!
Gazette Issue 7 August 2006 download

Finding a rare “lost gem” in a flea market gives an adrenalin rush that modern on-line auctions can never match. But what makes a slide rule rare is not straightforward as “rare” can turn out to be a simple pouch clip.

[ARISTO] [brand] [DIETZGEN] [[Eckel] [Escher] [Faber-Castell] [Keuffel] [K&E] [Leningrad] [Pickett] [P&E] [POST] [RICOH] [SIC]

Een 400 jaar oud rekenwonder / 400-year old calculating wonder (last updated: September 2011)
Private June 2006 download

Voor de hedendaagse scholieren en studenten is het nauwelijks te geloven dat tot omstreeks 1970 een 17de eeuwse uitvinding van een Engelse dominee het belangrijkste rekenkundige instrument was!

For today’s schoolchildren and students it is hard to believe that until about 1970 a 17th century invention by an English clergyman was the most important calculating device!

[Dutch] [Gunter] [Mannheim] [Napier] [Oughtred]

Slide Rules Are …… Music To My Ears! (updated IM2005 vesrion)
JOS Vol. 15 No. 1 April 2006 download

For centuries the slide rule proved an invaluable calculating aid. But there was another side to Oughtred’s invention. It proved highly adaptable and was used in many diverse ways – even for music!

[acoustic] [Blundell] [carillon] [Faber-Castell] [Fenning] [Fritsen] [harpsichord] [harmonics] [IWA] [Lawrence] [Lloyd] [nomogram] [Petit] [piano] [pipes] [organ] [Rensch] [Taylor] [transposer]

Hoe is het met jouw nauwkeurigheid? / How is your accuracy? (last updated: October 2012)
MIR No. 36 June 2004 download

Peter Soole’s eenvoudige manier om erachter te komen hoe de productie toleranties voor de juistheid zijn gesteld.

Peter Soole’s simple way to test any manufacture’s tolerances for accuracy.

[Dutch] [exactness] [precision]

The Saint Emilion or the Faber-Castell ??
Skid Stick No. 15 November 2003 download

I suspect, like many collectors, my family sees my passion for collecting slide rules as an eccentric and harmless hobby but storing away all the new additions can be a challenge?

A Rose by any other Name (last updated: August 2015)
Skid Stick No. 1 January 1999 download

When hunting for something like a “long forgotten” slide rule in other continents or even in some parts of Europe, English or hand/foot sign language is often not enough (n.b. original compilation by KRING member Jaap Dekker).

[foreign] [translate] [translation]