• 455 Martinson, Los Angeles
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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

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Click on any Model in the list for its full specification/details OR hover over its "Thumbnail" (if shown) for a pop-up enlargement:
A.W. Faber
ModelTypeCommentsThumbnail
(350)Enhanced MannheimUnmarked pre-runner to model 350 - cm scale in well of stock + INCHES to METER printed conversion scale on back
(368)ElectroV & W scales in well of stock + cm scale reversed + top & bottom edges bevelled
308/SPocket Enhanced Mannheim

promotional rule for: Osnabrücker Kupfer- und Drachtwerk

332Pocket Mannheimpromotional rule for: La Ceramique Nationale
339Mannheim“Made in Bavaria” on back
368 (ver. 2)Electro

V & W scales, DR Patent 206428 & DRGM 271169 & 247514 in well of stock + top & bottom edges bevelled

373Lilliput Mannheiminch scale on back
380Desktop Enhanced MannheimGold lettering + cm scale in well of stock - INCHES to METER printed conversion scale on back
51/39/339School Mannheim
51/87Rietz
51/91School Enhanced Mannheim“Import” stamped in back
52/22School Business

many gauge marks above top DF scale

52/39Mannheimunbranded but MARABU advertising logo (= reseller Marabuwerke AG, Tamm) printed on back
52/39/355School Mannheimcursor possibly not original
57/22School Business
A.W. Faber-Castell
ModelTypeCommentsThumbnail
1/22Business - early

Pre 1958 version with 2-part British currency bottom edge scale (later combined scale) - table of conversion factors on back

1/22Business - latePost 1958 version with combined British currency scale
1/22Business - late exportPost 1958 export (inch edge scale) version with combined British currency scale
1/22ABusiness AddiatorBritish pre-decimal £sd bottom edge scales - conversion tables + addiator on back
1/28Super Business - latePost 1958 version with combined British currency scale
1/48Machining - System Dr. Winkel
1/54 (ver. 1)Darmstadt
1/54 (ver. 2)Darmstadtscale annotations + extra peripheral hairlines compared with ver. 1
1/54mDarmstadt
1/60Enhanced Mannheim
1/60/360Enhanced Mannheim
1/77System Pickworth-likeUncommon model - cm scale in well of stock + conversion table on back + scale layout similar to 377 except K scale is not in back of stock but full-length on bottom edge
1/78/378Electrohand-drawn K scale on stock + V & W scales in well of stock
1/87 (ver. 2)Rietzcm scale in well of stock
1/87 (ver. 3)Rietz
1/87/387Rietz
1/87ARietz Addiatiorconversion tables + addiator on back
1/87mRietz

cm scale in well of stock - origin of model suffix “m” unknown

1/92Log-Log
1/98 (ver. 1)ElectroV & W scales in well of stock
1/98 (ver. 2)Electro

V & W scales in well of stock

1/98/398ElectroV & W scales in well of stock
11/54Darmstadt
11/98ElectroV & W scales in well of stock
111/22BusinessTwo-part British pre-decimal currency scales
111/38 400gSurveying Topography
111/54DarmstadtOriginal version without the later extra BI & ST scales
111/54Darmstadt - lateLate model with extra BI & ST scales
111/54ADarmstadt Addiator - lateLate model with extra BI & ST scales - Addiator on back
111/66 (ver. 1) DEMEGRAPH - System Schirmer

For graphic design - earlier version = F-C 2/66

111/87Rietz
111/87ARietz AddiatiorAddiator on back
111/98Electro
12/82Export DuplexOnly model in the 12/xx series + “inexpensive school” version of 2/83N
152/81Novo-MentorTwo-tone
152/82 (CH)School D-Stab

red & white insted of green & white colouring + MADE IN SWITZERLAND

157/87School Rietz
157/87School Rietz - blackmonochorme (black) version
157/89Log-Log
157/89Log-Log - black

monochorme (black) version

2/62Desktop Reinforced Concrete - System Dywidag extra long rule
2/82Duplex
2/83Novo-Duplex long-scale Green plastic rather than steel end-braces
2/83NNovo-Duplex long-scale

Impresiive 30+ scales including a unique combined D & LL0 scale

2/84Mathema Hyperbolic

Only hyperbolic model F-C made + unusually extra gauge points on side edges of cursor

20/45Bio-RhythmographMechanism built into a 2/83 style plastic box
20/66Typometer printingFor Didot 6-14 point print system - accessory for the 2/66 DEMEGRAPH rule
20/66/SL DEMEGRAPHTypometer printingFor use with F-C 111/66 System Schirmer
20/68ParifixConversion table rather than a slide rule
20/70Universal/Technical

Design by Dieter von Jezierski whilst a director of Faber-Castell

3/11Desktop Structural Engineeringspecial tables on back
3/31Desktop Reinforced ConcreteNomogram on slide and scales in well of stock
300586 S WaldnerPocket Noetpad wallet Rietz (67/87)Wallet black (= suffix S for “Schwarz” to model no.) on the outside but grey on the inside - most wallets, etc were promotional company branded gifts e.g. for German laboratory & science classroom supplier: Waldner
310/52Demonstration OHP School D-stab/Log-Log

Overhead projector version for model 52/82

310/88,89Demonstration OHP School Rietz-N/Log-Log

Overhead projector version for models 57/88 & 57/89

334/52Demonstration School D-Stab/Log-Log

Classroom version of model 52/82

334/87Demonstration Rietz

Classroom version for all models with Rietz scale layout

342 (ver. 2)Desktop Columbus Business long-scale - System Rohrberg

Joint branding with KLAWUN + 1st F-C specialist rule for Merchants - extra wide body

360 (ver. 1)Enhanced MannheimRailway track scales
360 (ver. 1)Enhanced Mannheim - earlyRailway track scales + cm scale in well of stock
360 (ver. 2)Enhanced Mannheim
360 (ver. 3)Enhanced Mannheimwider cursor than other 360s
361Mannheim (double bevelled-edged)cm scale reversed + top & bottom edges bevelled - see: My Tech Papers “Mind the Edge”
361 (ver. 1)MannheimRailway track scales
361 (ver. 2)Mannheim
363Enhanced Mannheimcm scale in well of stock + MADE IN BAVARIA on both box & stock
367Enhanced MannheimNo cm scale in well of stock - metal strips
375 (ver. 1)RietzRailway track scales
375 (ver. 2)Rietz
378ElectroV & W scales in well of stock
379Pocket Electroelectro conversion table on back
387Rietzcm scale in well of stock
398ElectroV & W scales in well of stock + short temperature scale on B
4/22Desktop Business

conversion table on back

4/38Desktop Topography
4/54Desktop DarmstadtNo blind date stamp - coversion tables & factors on a plastic book-mark
4/54Desktop Darmstadt - earlyConversion tables & factors on back
4/87Desktop Rietz
4/98Desktop ElectroV & W scales in well of stock
44/87Desktop RietzPart of unusual limited series made from high pressure laminated (HPL) wood with metal inserts - patent no. DE892693
52/80Mentorcracked cursor
52/81Novo-Mentor
52/81 (CH)Novo-MentorMADE IN SWITZERLAND version
52/82School D-Stab/Log-Log
52/82School D-Stab/Log-Log - early

BI, LL1, S’ & P scales only added to layout post 1961

52/82 (CH)School D-Stab/Log-Log

MADE IN SWITZERLAND version

57/22School Business
57/67Philips - meterology (dew point & humidity)Unmarked - Philips no.: Z9.151.98
57/69Central Heating Capacity

Patented design (NL81186) for calculating optimum capacity for central heating systems was part of a Dutch heating industry course: Stichting Vakcursus Verwarmingsartikelen En Kookapparatenhandel

57/74 (ver. 1)Textile System Schirdewan - metric

Original metric version with unique A’ scale - read more ...

57/74 (ver. 2)Textile System Schirdewan imperial

A’ scale from version 1 replaced by LL + wider Imperial version cursor + cm scale on back - read more

...

57/74 (ver. 2)Textile System Schirdewan metric

A’ scale from version 1 replaced by LL + inch scale on back. Read more

...

57/86Mannheim Columbusnarrow
57/87School Rietz
57/88School Rietz-N
57/88 (CH)School Rietz-N

MADE IN SWITZERLAND version

57/89School Log-Log
57/92School Log-Log
61/60Pocket Enhanced Mannheim
61/60/369Pocket Enhanced Mannheim
62/82 (ver. 1)Pocket Duplex
62/82 (ver. 2)Pocket Duplex
62/83Pocket Novo-Duplex long-scale
63/22Pocket Business
63/22RPocket Business AddiatorBritish pre-decimal £sd bottom bevelled edge scales + pen for addiator part of stock - Addiator on back
63/39Pocket Mannheim
63/87RPocket Rietz Addiatorpen for addiator part of stock - Addiator on back
63/91Pocket Enhanced Mannheimpromotional rule for: Atlas Diesel
63/98Pocket Electro
67/22Pocket Businessfor pre-decimal British £sd
67/22RbPocket Business Addiatorfor pre-decimal British £sd - Addiator on back
67/34Pocket Hämognost - Medical, Dr. VogelSpecially for haemoglobin/blood analysis
67/39Pocket Mannheim
67/54Pocket Darmstadt
67/54 BayerPocket Darmstadt
67/54bPocket Darmstadt
67/54RPocket Darmstadt AddiatorAddiator on back
67/54RbPocket Darmstadt AddiatorSpeical IM1997 version - Addiator on back
67/54RbPocket Darmstadt Addiator - ExportHenderson, Lindsay& Michaels Inc. (Greenville B.C.) stamped on back of pouch - Addiator on back
67/56bPocket Welding - Schweisstechnik, System TitscherSpecially developed for welders + related formulas the back
67/74Pocket BASF Pigment-Volume-ConcentrationUnusually for a “special commission” (BASF) it has a standard F-C model number in the 6x/xx series + table of pigment thicknesses on back
67/87 ArtosPocket Rietz
67/87 SKFPocket Rietz
67/87RPocket Rietz AddiatorAddiator on back
67/91Pocket Enhanced Mannheim

model no., etc printed on back because of advert in well of stock

67/98 (ver. 1)Pocket ElectroV and W scales in the well of the stock + “import” stamped in back
67/98 (ver. 1)Pocket Electro - imperialV and W scales in the well of the stock
67/98bPocket Electrob model suffix = wider stock
67/98RbPocket Electro AddiatorAddiator on back
77/91Lilliput Mannheim42nd Wedding Anniversary present from Ros
8/10 BASFRietz

1 of only 8 circular production models F-C made

8/12 DELBAGResistance in metal pipes

1 of only 8 circular production models F-C made

8/20Pocket Basic42nd Wedding Anniversary present from Ros - 1 of only 8 circular production models F-C made
8/30Pocket RetailOuter scale is for calculating a % discount or % surcharge - 1 of only 8 circular production models F-C made
BASF Tonband-Schmalfilm-RechnerPocket Home Audio & Cine Film - System Schirmer

Reused 67/22b body for special commission - 8mm & 16mm frames/minute nomogram on back - is this Schirmer the same as the Demegraph Max Schirmer? ​

ESSO ViskositatCrude Oil Viscosity V.I. 70-80

Made for US global oil major: ESSO. Conversion tables on back

Heine RealzeitscheibeNetwork PlanningF-C marked - special commission for Firma Georg Heine, Stuttgart
Hel (cme)Richtschieber A - Artillery

cme = F-C secret code for being made by Wichmann in Berlin - Eagle stamped in well signifying German military authorities - notches top & bottom either end of slide & 4 ball bearings in well stop slide accidentally falling out + plastic stops either end of bottom edge to stop cursor sliding off

Laukhuff OrgelpfeifenDesktop Music Organ Pipes - System Rensch

Made for German organ builder: Laukhuff. Company still operating. For scaling organ pipes (wood/metal flues & reeds) - superb quality but only 500 ever made - Orgelbau-Verlag started selling their own (inferior) version in 1986

Nijgh & Van DitmarTechnical

Made for Dutch publishing company: Nijgh & Van Ditmar - founded in 1843 it is still operating - standard scale layout but for unusual folded scales was reputedly to complement a book on calculating tips & tricks (including folded scales speeding up certain types of calculation) - pictograms on back same as on the model 57/86 

Peddinghaus Stanz- und SchnittkraftSteel punching & cutting forces

Made for German specialist steel plate supplier: Peddighaus. Company still operating. Table of maximal punching forces on back.

TR1 (ver. 2)Hybrid electronic calculatorSerial No. 015050144 - scale layout chosen to complement basic calculator functions
TR2Hybrid electronic calculatorSerial No. 027090384 - scale layout chosen to complement basic calculator functions
TR3Hybrid electronic calculatorSerial No. 034110034 - scale layout chosen to complement extended calculator functions
TR4Electronic calculatorSerial No. 046110135 - without slide rule but with extended calculator functions
Verlag ChemieChemical

Made for German specialist publisher: Verlag Chemie. Unconventional layout of scales on front with specialist scales + gauge marks for many elements & compounds on back. ​

Versuchs- und Lehranstalt für BrauereiBeer Brewing - System Windisch

Made for a German institute supporting the beer brewing industry: Glasbläserei der Versuchs- und Lehran-stalt für Brauerei - also issued as model 51/80

Abbot Brown & Sons / Smiths (Calculators)
ModelTypeCommentsThumbnail
Blackwell Average Speed Calculator Mk ITime-Speed-Distance rallying calculator Design patented (GB707740) by Harold Blackwell - surprisingly stamped on back “obtainable from Blackwell’s Metallurgical Works Ltd” (was Harold part of a family business?) - later larger duplex Mk II version made
LeeSheet Steel Weight Calculator

For calculating the weight of one or more sheets of steel according to size/thickness of the sheets - made for H.F. Spencer Ltd. - carries the later name of “Smiths (Calculators) Ltd” after Bill Smith sold out to John James

Resistance Chart for Viscous Flow OnlyPipe flowUnmarked/unbranded but style & finish very Abbot Brown like - probably a Stohert & Pitt Ltd advertising giveaway - company folded in 1989 & name sold to Langley Holdings  
Thermocontrol Heat Transmission CalculatorUnmarked/unbranded but style & finish very Abbot Brown like - specially commissioned by Thermocontrol Inst. Co. Ltd
Addiator GmbH
ModelTypeCommentsThumbnail
ADDFEETImperial Slide Adder - gold/green

For non-decimal adding/subtracting in feet, inches & 8ths of inch - baby brother version of larger SIZEMATIC model

ARITHMASlide Adder - silver

For adding/subtracting but cheaper/simpler version of UNIVERSAL model

CALCULEXMultiplication Table

Simple but patented (DE1839275) device mainly for obtaining percentages of values - not to be confused with earlier 1923 slide adder or pocket-watch slide rule types of the same name ​

CREDIT-DEBETSlide Adder (saldo neg.)

Serial no. M 922692 for book-keeping adding/subtracting but with additional display line for negative balances (saldo neg.) on DEBET side

DUPLEXSlide Adder - silver

Extended/bigger version of the ARITHMEA model​ - many DUPLEX versions sold

HEXADATHexadecimal Slide Adder for Computer Programmers

Serial no. 670306 patented (DE1963993) design for adding/subtracting in base 16 - table of hex/dec equivalents on back - possibly most impressive & complex slide adder ever made - read more ...​

MAXIMATOR/STORAGESlide Adder (saldo neg.) set (2) - gold/green

Serial no. 214840 front hinged adder for adding/subtracting but with additional display line for negative balances (saldo neg.) on subtraction side - smaller adder underneath for storing interim or working results (modern memory function) ​

SIZEMATICImperial Slide Adder - gold/brown

Serial no. 695205 - for non-decimal adding/subtracting in feet, inches & 16ths of inch - big brother version of ADDFEET Junior model

UNIVERSALSlide Adder (saldo neg.) - gold

For adding/subtracting but with additional display line for negative balances (saldo neg.)

Addimult Rechenmaschinenfabrik
ModelTypeCommentsThumbnail
SUPRASlide Adder

Made in Sweden for adding/subtracting but because of Addiator metal sheath/case possibly a transition model as son Hans-Wolfgang Kübler set up his own business after working for his father Carl at Addiator

Aristo
ModelTypeCommentsThumbnail
010608 Studio Desktop Technical/Log-Log

Extra wide ​- 25cm (no. 0968) & 12.5cm (no. 868) versions also made

01070 MultiLog Desktop Technical/Log-Log

Extra wide ​- Multilog v/s Studio = extra LL00 & LL0 scales - 25cm (no. 0970) & 12.5cm (no. 870) versions also made

101 Junior Demonstration OHP School/Technical

Overhead projector version for model 0901 - see also Classroom version - Junior = range for high schools

1055Desktop Commerz I Business

Series of imperial to metric conversion gauge marks on lower front face - s-d-£ scale is folded - inch scale on back - 25cm (no. 955) & 12.5cm (no. 845) versions also made ​

1067 UDesktop Darmstadt

​inch scale on back

168 Studio Demonstration OHP Technical/Log-Log

Overhead projector version for models 868 & 0968 - Studio = range for more technical disciplines

206/1&2 BiScholarDemonstration School 35mm Slide Projection Set

44nd anniversary gift from Ros - boxed set of two lantern slides specifically for manual feed 35mm photographic slide projector - BiScholar = range where a Sine scale is included on stock & on slide - demo version of 0906

30050 Lindell "55"Desktop Transversal Planimeter

No slide - specially commissioned by Finnish stationers Ab Herman Lindell Oy - for measuring distances/areas - cursor extension suggests results were transposed for further working - name Herman Lindell + “import” & “copyrighted” in Finnish on the back

301 Junior Demonstration School/Technical

Later Classroom version for model 0901 - see also OHP version - Junior = range for high schools

303 LL Scholar Demonstration School/Log-Log

Later Classroom version for model 0903 LL - Scholar = general schools range

670Pocket KeyRing/Time-Speed-Distance Travel Calculator for Motorists

Front for conventional time-speed-distances km/hour - back for fuel economy Litres/100 km - B&W version also made + sibling 671 model calibrated for imperial units (miles & gallons) ​

939Reinforced Concrete - System Göttsch

Sale item​

99Demonstration/Display Darmstadt

100% Geretsried made dummy - slide does not slide - “Ausstellugsmuster” on back

99 Demonstration/Display Darmstadt - early

100% dummy - slide indented but does not slide - “Ausstellugsmuster” on back

Aston & Mander
ModelTypeCommentsThumbnail
Hill'sArtillery for indirect fireArm length 26” scale, a table for fuse rating of 18pr for ranges <2000 yards, a Flight of Time (T of F) table in seconds/thousand yards & a synopsis of “Orders” on back
Aston, J.
ModelTypeCommentsThumbnail
Carpenter Timber No. 22060Joint 2-fold Tunnel-hinged Coggeshall

D GIRT line = 4–40 with IMPL GAL gauge point - unbranded but font & model numbering identical to known J. Aston + two-entry ½ & ¼ scale table on front + E & M scales (split over 2 legs) on back.

Aston, T
ModelTypeCommentsThumbnail
Hawthorn EngineerJoint 2-fold Old Arched-hinged Coggeshall

D Girt line = 4-40 + structural conversion & material gauge marks on front + “Extreme Strain” tables of material compression strengths & conversion measures on back

Ausschuss fuer Wirtschaftliche Fertigung (AWF)
ModelTypeCommentsThumbnail
SR 701Machining time poly-slide (2)made by Hans Seehase & designed by Friedrich Bahlecke (1928-1930) - table of factors on back
SR 726Gas pipe line high & low pressure poly-slide (2)made by Hans Seehase & designed by Hans Schwerdt - SG and conversion tables on back
SR 751Blank but with hand-drawn scales for Machining

made by Hans Seehase - now in the collection of fellow collector Karl Kleine

Berville, P
ModelTypeCommentsThumbnail
(NoName)Pocket Mannheim

Probably made by MARC (OEM of No. 2) - inch scale & Werf Gusto. Firma A.F. Smulders, Schiedam on back

BIOMATE (UK) Ltd.
ModelTypeCommentsThumbnail
BiomateBiorhythm Calculator

Patented design (GB1446576) by A.F. Green for finding biorhythms (for ages 1 to 80) for any given day of the year - late 19th century theory (no proven scientific basis) developed by German physician Wilhelm Fliess for 3 biorhythm cycles: physical (red 23-day cycle), intellectual (green 33-day cycle) & emotional (blue – 28-day cycle)​

Blundell Brothers/Rules Ltd. (BRL)
ModelTypeCommentsThumbnail
## Double SharpSteel Weight Calculator (Model A)

Made for James Austin & Sons, Dewsbury, UK - slide behind a window rather than closed frame - table of decimal equivalents of fractions in well of stock - steel bar & sheet conversion aids on back of slide & stock - see Skid Stick No. 10, February 2001

0552-160219Bearing Rate (Mark I Model 0)Navigational Instrument (6605) for British MoD - National Stock Number: 6605-99-462-3859 - unmarked
0552-160221 / P2297Torpedo Spreading poly-slide (2)Navigational Instrument (6605) for British MoD - National Stock Number: 6605-99-462-3861
304Academy Darmstadt

White end-braces on back of stock

308Academy Accountant's and Business

For per-decimalisation £,s,d (UK went decimal 1971)

310Pocket AcademyConversion fan table on back
644944 / P5284Radiac Nuclear Fission Products poly-slide (2)Hazard-Detecting Instruments and Apparatus (6665) for British MoD (99) Stock Number (911-0027) © Admiralty Research Laboratory, UK for calculating external radiation doses - RADIAC = Radio-Activity Detection, Identification & Computation
6665-110060Radiac Nuclear Radiation Calculator No.1 (NL version for land)

Smaller Dutch version for calculating radiation contamination on land in training exercises

6665-99-911-0117/0060Radiac Nuclear Radiation Calculator No.1

Designed by William Orr (1951) + BRL Mod/NSN Nr.:6665-99-911-0060 made for British & Canadian Governments + intermediate & inner discs are double-sided: (i) pink for contamination over LAND & (ii) blue for contamination generated at SEA - centre split washer to flip sides

80543Omega Artillery Mils (MK2)

Fire Control Computing Sights and Device (1290) for British MoD - National Stock Number: 1290-99-960-0933 - Trig scales are in Mils (6400 mils = 360 degrees)

AG2Rietz-likeReplacement for G.2 model - tensioning pins in edge & cm scale on back
AL6Log-LogReplacement for L.6 model - tensioning pins in edge & inch scale on back
BlakeboroughValve SizingModel name = Joseph Blakeborough & Sons Ltd. - West Yorkshire engineering business (1866-1989) specialising in design & manufacture of industrial water valves - for choosing correct size valve based on a calculated flow coefficient
C24 DCost & Profit Reckoner RetailModel suffix “D” denotes later model with all-plastic 1-piece moulded “Diakon” cursor
E.3Electro

Conversion table on back - Batch No. 299 + tensioning pins - read more ...

G.1 Student Enhanced Mannheim without TrIg scales

Cheaper model with no stove enamelling on the back - Batch No. 533 + tensioning pins - read more ...

G.1 (reject)Student Enhanced Mannheim without TrIg scales

Batch No. 101 - top front edges shaved off & “SUBSTANDRD” stamped in back - one of many as “waste rate” was +/- 50-60% of all production! - read more ...

G.2Enhanced Mannheim without Trig scales

Conversion table on back. Batch no. 1923 + tensioning pins - read more ...

G.2Enhanced Mannheim without TrIg scales - early

Plain back - No batch no. - read more ...

G.5Enhanced Mannheim

Conversion table on back - Batch no. 365 + tensioning pins - read more ...

HolophaneAngle Lighting Calulator

Batch No. 1952 + tensioning pins - read more ...

HolophaneIllumination Lighting Calculator

Batch No. 655 + tensioning pins - read more ...

L.4Log-Log

Conversion table on back - Batch No. 468 + tensioning pins - read more ...

L.6Log-Log

Company name “Taylor Woodrow”+ conversion table on back - Batch No. ?51 + tensioning pins - read more ...

LakerCutting Speed/Feed Calculator

Design copyrigh: Firth Brown Ltd - batch No. 249 + table constants & conversion factors on back - read more ...

P.8Pocket Mannheim

Conversion table on back - Batch No. 591 - read more ...

P.8Pocket Mannheim - early

Mottled/fading of enamel - Batch No. 337 - read more ...

P.8Pocket Mannheim - late

Conversion table + ICL COMBUSTION on back- Batch No. 1843 - read more ...

P1418Shell-Mex & BP Room Volume Calculator

Made for Shell-Mex/BP (SMBP) Ltd

P1442Shell-Mex & BP Friction Loss CalculatorMade for Shell-Mex/BP (SMBP) Ltd - conversion constants on back
P1454Pipe Flow

Made for ICI (no. 230) - nomograms and a table on the back

P1553Armstrong Calculator for Flooring

Made for Armstrong Cork Co. Ltd., London for calculating cost in sq. yards/feet to tile a floor area and/or the number of 9” x 9”/12” x 12”/18” x 18” floor tiles needed - grey end-braces on back of stock

P17Log-LogOne of replacements for P.8 model - cm scale on back
P1732/AFisher Valve Sizing Mark III F

Copyrighted French version made for Elliott Automation based in Paris

P1960/BPaint Calculator (folded £-s-d scale)

Made for Sissons Brothers & Co. Ltd., Hull, UK - grey end-braces on back of stock - spreading/coverage rates for types of Sissons’ household paints on back

P2245Textile yarn count conversion aid

Slide chart made for Bentley Group, UK

P2304Paper Substance Calculator

Promotional give away made for commercial paper manufacturer & merchant: The Wiggins Teape Group, High Wycombe, UK for calculating length & weight of a reel for a given weight of paper (grams/m2 ) & width - grey end-braces on back of stock

P2327 (P4409)Percentage Overlap on metal seams

Made for Metal Box Company Ltd (UK) - P2327 old no. for Halden version but MB version should be P4409

P2808Ultrasonic poly-slide (2) for testing metal buttt welds

Original training/testing version made for inventor J.W. Fox (Brit living in USA - hence American 1967 © design) & Schoool of Applied Non-Destructive Testing, London (SANDT) - design later sold to M. Falk & Co & a simplified version (using standard components & a duplex cursor) reissued as BH P4366

Paper Facts & FiguresPaper Calculating Rule

Unmarked reused Academy 300 series blank for Paper Facts & Figures Ltd. - specialised scales/method for paper distribution calculations by paper buyers, estimators, etc. - unusually scales on back for an open frame construction

T.20 Technicians Desktop Log-Log

No batch number but 4 tensioning pins & 4 chiselled out recesses in each end of top & bottom side edges to combat Bakelite shrinking problems + plain Bakelite back - read more ...

T.50Janus Multi Log-Log

Janus logo = dual-faced (future & past) Roman god of beginnings & transitions

U.7 UniversalLog-Log

Conversion table on back. Batch No. 609 + tensioning pins - read more ...

Blundell Harling Ltd. (BH)
ModelTypeCommentsThumbnail
500Academy Log-Log

Includes highlighted yellow strips on cursor for reading off A/B & C/D scales on front & C/D scales on back

6665-99-780-8137Radiac Nuclear Radiation Calculator No.1 Mk2

Later variant of BRL Mod/NSN Nr.:6665-99-911-0060 version + intermediate & inner discs are double-sided: (i) pink for contamination over LAND & (ii) blue for contamination generated at SEA - centre split washer to flip sides

6B/1112682Hercules C.Mk.1 Aviation Trim Computer

Made for UK MoD & designed by H.O.A.S.C. Operation Research department of RAF - table of fuel movements on back

802Academy Log-Log
803Academy Rietz

B & C scales highlighted in yellow

812Pocket Classmate Academy Rietz
813Classmate Academy Rietz
904Academy Darmstadt

Same construction as Academy 800m series but with double-sided interlocking convex cursor

905Academy Log-Log

Same construction as Academy 800m series but with double-sided interlocking convex cursor

M899Pocket Electro Power Factor calculator

Slide Chart made for British Insulated Callender’s Cables Ltd (BICC) - © UKP/7M/262 on back​

NL 11-95Pocket Memorial

1 of only 100 made especially for the IM1995 - the inaugural Int. meeting held in NL

P2734AFisher Valve Sizing Mark VCopyrighted version made for GEC-Elliott Valves Limited
P3679Music Chord Computer

Slide chart specially commissioned by UK copyright holder Dudely Fulller Associates - design invented by musician Dudley Fuller

P4463Illuminanace & Angle Calculator

Follow-on (after two decades) special commission by Holophane Ltd to replace two BRL bakelite models: the Illumination and Angle calculators. These two calculators were the inspiration for Blundell to start the highly successful “P” series of specially commissioned slide rules.

P4743Fisher Valve Sizing Mark VIII

Copyrighted version made for Fisher Controls

P5092Oil Fuel Viscosity-Temperature Calculator

Commissioned by British Petroleum (BP) Trading Ltd. - later version of an unbranded but BH-made b&w version of the same calculator

P5154Beer/Lager Retail Price Calculator

Slide chart made for Courage Brewery - front for draught/barrel beers/lagers & back for bottled beers/lagers - unusually it integrates the Value Added Tax (VAT)

P5527Roof Pitch Indicator

Slide chart made for Marley / Chestnut Roofing Supplies Ltd

P5731Music Note Tracker

Slide chart made for UK patent holder (GB2245409) Peter Davies.

Robert Jenkins Co. LtdPocket Tank Capacity Calculator

Unbranded but identical to earlier BRL/BH “P” versions - design by Alan Menmuir -

S143-10School Rietz without trig scales
S150-10School Rietz
S150-20Pocket School Rietz
W.H. Smith Student Log--Log

One of three generic BH-made models sold by UK retailer/stationer W.H. Smith

Bradburn & Sons, T.
ModelTypeCommentsThumbnail
Carpenter TimberJoint 2-fold Bradburn's Bolted-hinged Coggeshall

D Girt line = 4-40 + five-entry ¼ to INCH scale table on front + Lion trade mark + half-length E & M scales (split over 2 legs) on back

British Engraving and Nameplate Manufacturing
ModelTypeCommentsThumbnail
Bonwitt 5403 long-scale(ish)Only known model of maker - British Engraving (with Edward Holliday) granted patent GB618135 for their engraving method in 1949 - meaning of Bonwitt model name unknown.
British Slide Rule Co.
ModelTypeCommentsThumbnail
The SupremeStudent Log-Log

Tables of conversion constants on back

The Technical StandardLog-Log

Tables of conversion constants on back

Carbic Ltd / Otis King
ModelTypeCommentsThumbnail
Fischer CalculatorHelical long-scale

Invented & patented (GB778556) by Rafael Fischer in 1957 - 4 equidistantly spaced red positioning arrows on the inner moveable plastic sleeve

Model K 2nd versionPocket 07 helical long-scale white on black

Serial No. B1086 - both the presentation box & white on black paper scales are rare

Model K 2nd versionPocket 11 helical long-scale brass

Serial No. P2601 - brass sleeve probably only result of original black paint wearing off

Model K 2nd versionPocket 12 helical long-scale

Serial No. S0702

Model L 4th versionPocket 03 helical long-scale

Serial No. A8920

Model L 4th versionPocket 13 helical long-scale

Serial No. Z3168

Casella, L.P.
ModelTypeCommentsThumbnail
(NoName)Desktop "prototype"

Stamped CASELLA but possibly made by UK maker W.H. Harling - upside-down scales on the slide probably a design feature when inverting the slide - read more ...

Anderson ImprovedLong-scale extra precision

Three extended non-standard scales (Patent GB190309095 - Major F.J. Anderson) respectively folded 4/4/7 times for extra precision + “Supplied by W.H. Harling” blind-stamped in back + 778 stamped in left-hand side edge

Danfoss
ModelTypeCommentsThumbnail
(NoName)Pocket Refrigerant - early

No slide

(NoName)Refrigerant

No slide

520H4713RefrigerantNo slide
CalculatorHeating flue gas lossesCalculations based on a standard calorific value of fuel oil - back of calculator gives fuel oil nozzle capacities
RT.00.A1.00 RefrigerantNo slide
RT.00.A2.00RefrigerantNo slide
RT.0X.A5.00RefrigerantNo slide
Dargue Brothers Ltd / Simplon
ModelTypeCommentsThumbnail
BilateralLog-Log - early

“Half-duplex” layout with scales on back of a “closed frame” stock & extra-wide cursor track for reversing cursor - early production model because patent (GB413308) is still pending

S.B.10 BilateralLog-Log

“Half-duplex” layout with scales on back of a “closed frame” stock & dual cursor tracks for reversing cursor

S.B.5 Bilateral Pocket Enhanced Mannheim

“Half-duplex” layout with scales on back of a “closed frame” stock & reversible cursor

S.E.10 (Bilateral)Electro

“Half-duplex” layout with scales on back of a “closed frame” stock & dual cursor tracks - W & V scales in well of stock - degree (<5

˚34’) to Tan & degree (70˚-90˚) Sin conversion tables also on back of extra wide slide + table of conversion factors on back

S.M.10 Major (Bilateral)Log-Log

“Half-duplex” layout with scales on back of a “closed frame” stock - chamfered opening used instead of reversible cursor - degree (<5˚34’) to Tan & degree (70˚-90˚) Sin conversion tables also on back of slide + table of conversion factors on back

S.P.10 PrimaryLog-Log

Extensive table of conversion factors on back

S.P.5 PrimaryPocket Mannheim

Extensive table of conversion factors on back

S.R.10 BilateralRietz

“Half-duplex” layout with scales on back of “closed frame” stock & extra wide single track for reversing cursor

S.R.2 Sub-IvoryPocket Mannheim

“Sub-ivory” from unusual orange colour plastic (possibly form of bakelite) - Identical to S.R.-1 except this model has studier full-view glass cursor - unusually with original case ​

S.R.5 Sub-Ivory Uniface Technical

“Sub-ivory” from unusual orange colour plastic (possibly form of bakelite) - “Uniface” name comes from S & T scales being on front face instead of back of slide

XL-10 (Bilateral)Log-Log

Identical strange “half-duplex” layout with scales on back of a “closed frame” stock & dual cursor tracks as Bilateral models BUT the divisions on 2 & 3 cycle A & D scales on back run respectfully just from 0.01-1 & from 0.1-1 

David (Emile)
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CalculimetrePocket Charpentier MannheimWonderful 40th Wedding Anniversary present from Ros
Dennert & Pape
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Aristo 1067 UDesktop Darmstadt

D&P name in well of stock - ​inch scale on back

Aristo 109 Desktop Rietz
GWRDesktop Military Naval Artillery

Instruments for German armed forces used codes to hide maker’s identity - GWR​ = D&P - besides solving normal artillery-related distance problems, this naval version also takes into account drift of a moving vessel

IVDesktop Enhanced Mannheim

IV = model with 4 adjustment screws in bottom edge - railway track scales - cm scale in well of stock​

QR 41Desktop Military Artillery Squaring

QR = “Quadrat-Rechenschieber” - commissioned by “Gebr. Wichmann” (stamp in well) - intended as classroom training aid for anti-aircraft gunners - layout consists of two pairs (upper set 0 - 50 & lower set 0 - 15.8) of non-logarithmic independent squaring scales (no interaction) derived from a set of tables by German Peter Timpenfeld & first published in 1888​

Diefenbach
ModelTypeCommentsThumbnail
WMNPocket Water Pipes - System MulderWMN = Waterleidingbedrijf Midden-Nederland & table of flow factors/speeds for various pipe/conduit sizes on back
Dietzgen
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1752Desktop Maniphase/Enhanced Mannheim

Going by style of π gauge mark probably made by D&P + Maniphase = Dietzgen​ name for an Enhanced Mannheim + slightly longer slide + 6 adjustment screws & conversion table on back

Dimier
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ElectricPocket ElectroW scale in well of stock - COMPAGNIE GENÉRALE D'ELECTRO-CÉRAMIQUE & cm scale on back
Disney (Walt Disney Productions)
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Mickey Mouse Child's Disney World Teaching Aid/Calculator for Simple Arithmetic & Conversions

Child’s arithmetic slide calculator - made in Hong Kong - identical but later version known as: “Mickey Math Slide Rule”​

Slide Matching Child's Teaching Aid/Toy Puzzle poly-slide (3)

Made by MARX in Hong Kong - tile matching toy puzzle in form of slide rule featuring 8 vintage & much loved Disney characters

Dring & Fage
ModelTypeCommentsThumbnail
(NoName)Desktop Alcohol Gauging

Post 1824 because of IM B & IM G gauge marks signify change from Winchester to Imperial based measurement - bottom Seg Ly. scale is for gauging when the cask is lying on its side

Carpenter TimberDesktop Coggeshall

Rare rectilinear Coggeshall with 4–40 GIRT LINE for volumes of round timber + 2 sets of brass gauge pins (marked 0,16, 8 & 8,16, 0 respectfully) for round, 8 or 16 sided timber + INVERTED LINE (AI scale) for volumes of rectangular timber - compared to Langley version layout front & back reversed

Customs & Exercise D-F-52Desktop Alcohol Gauging Head Rod

Seg Ly. scale on front face is for gauging when the cask is lying on its side + SPH’D scale on back face is for calculating the spheroid

Mark VI Desktop Artillery for Indirect Fire

Serial no. = 36 - called Apparatus for the Observation of Fire was intended for use by lance-corporals & corporals - issued by Min. of Defence (inventory no. 302SB) ​

Durford / Tiger Toys
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"Blue label"Demonstration Mannheim

Accurate for a demo rule - has 4 spring-loaded tensioning metal balls in bottom slide track

DUVAL, Roger
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(NoName)Desktop Rietz + LL

Little known French maker (Drancy, Paris) - noticeable similar to Graphoplex made SRs - extra wide - top LL scale not standard for Rietz giving unconventional scale layout

EASY Slide Rule Co.
ModelTypeCommentsThumbnail
EasyEnhanced MannheimDesigned and patented (GB117318) by Capt. Albert Charles Chew, British Royal Artillery
Ebmeyer, H.W.
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TaremaSlide Adder

TaReMa model name = TaschenRechenMaschine or ​pocket calculating machine 

Educational Novelty Co.
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"Consul" The Educated Monkey Child's Teaching Aid/Calculator for simple arithmetic

Invented & patented (US1188490) by William Robertson in 1916 - “Consul” = name of famous performing monkey of the day - set x & ÷ problems with feet - results framed by monkey’s hands ​(+ & - problems need Addition Table card)

Engineering Instruments Inc.
ModelTypeCommentsThumbnail
10-BSelf-Teaching Encyclopaedia

Cadillac Publishing Co. free give-away unmarked “10-B” with vol.1

10-B (umarked)Enhanced Mannheim without Trig scales

Unmarked “10-B” with conversion & gauge mark tables on back

10-BKEnhanced Mannheim without Trig scalesStandard Lawrence 10-B but called 10-BK with conversion tables on back
250-BTEnhanced MannheimConversion tables on back
250-BT - plainEnhanced MannheimUnmarked - coversion tables on back
250-VEnhanced MannheimConversion tables on back
5-BPocket Enhanced Mannheim without Trig scales

Unmarked “5-B”

5-B LearnerPocket Student Enhanced Mannheim without Trig scales

DRAFT-A-PLAN BY LAKESIDE printed on rule

77AAmerican Log-Log

OEM rule made by ACU-Math (model 150) - unusual layout means the back is often mistaken for the front

Draft-a-Plan kit (5-B)LAKESIDE boxed setOEM collaboration between Lakeside &  Engineering Instruments 
Engineering Mfg. Co.
ModelTypeCommentsThumbnail
Calc-SlideEnhanced Mannheim without Trig scalesstrange raised wings of the cursor design
EURATOM
ModelTypeCommentsThumbnail
Brinck - De WoldeGeochemicalComplex rule invented by Herman de Wolde for calculating the probabilities of the world-wide presence of metal deposits - 1 of only 5 ever made
Farmar, F.C.
ModelTypeCommentsThumbnail
Publicans' RuleStandard for Licensed Victuallers

Retail rule to help publican’s calculate over/under proof alcohol, gauging, blending, stocktaking, discount and profit + Altimeter top-edge line for measuring the height of liquid in a bottle

Wine & Spirit Merchants' RuleDesktop Standard for Wine & Spirit Trade

Rule for entire trade to calculate over/under proof alcohol, gauging, blending, stocktaking, discount & profit + Gloucester Terrace address

Fearns Calculators
ModelTypeCommentsThumbnail
A13 Circular Slide RuleLog-logLL scale to base 10 - tables of conversion factors on back
A14 Circular Slide Rule / Conversion CalculatorLog-log conversionFront identical to model A13 but in separate part of wallet interchangeable extra outer disc with different conversion scales
Farmer's Weekly Metric ConverterConversionFarmer’s Weekly is a magazine started 75 years ago for farmers & agricultural businesses & is still being published weekly - conversion C & D scales double-up for simple multiplication, etc - extra conversion tables on both sides
Fenwick Dew Point & Relative Humidity CalculatorWhirling or aspiratted hygrometer humidity Special commission for Fenwick Inspection Services Ltd., Southampton - 2 look-up windows in top disc
RS Stock No. 620-547 (A6)Screw Thread Metric ConverterSpecial commission for Radiospares (RS), Australia - company still operating & selling the same converter
Fearns, Mear & Co.
ModelTypeCommentsThumbnail
AUDCO Pipe Flow CalculatorTurbulent pipe flow of liquids & gassesDesigned by Norman Mear for Auderly Engineering Co. Ltd (AUDCO) - parts engraved by United Chemical Engraving Co. before assembled in-house - back for calculating Reynolds No. to check flow was turbulent
Festus Mfg. Co. / Acu-Rule Mfg. Co.
ModelTypeCommentsThumbnail
Acu-Math 150Log-log

Unusual layout means the back is often seen as the front - identical to 150A except here end-braces added for extra rigidity & cursor is adjustable

Acu-Math 4Student Enhanced Mannheim without Trig sales
Acu-Math 401Student Enhanced Mannheim

Having Trig scales on front face was supposed to make it easier to use - moulded cursor bought in from American Molding Co., St. Louis - cursor tension spring bought in from Midwest Spring Co., St Louis

Acu-Rule 10-DEnhanced Mannheim without Trig scales

Often mistakenly thought to have been made by Lawrence - table of equivalents on back

Acu-Rule AREL G-W PhotoPhotographic

Unlike any other Acu-Rule made model for determining diverse photo-related of settings - photographic supplier AREL Inc. sole distributors - G-W = designers C.G. Goodchild & L.V. Whitney - conversion & notes on back

Acu-Rule MR700 Mu-StickMusic chord finding & key transposition

Unlike any other Acu-Rule or music type - design copyright Mel McSwain - sole distributor: McSwain Co., Arkansas

Acu-Rule Van NostrandEnhanced Mannheim

OEM for retailer & publisher: D. Van Nostrand, New York - table of equivalents on back

Acu-Rule Yoder 103Enhanced Mannheim

OEM for Yoder Instruments, Ohio (related company : Lafayette) - table of conversions on back

Festus (100)Enhanced Mannheim without Trig scales

Same stock as later Acu-Rule model 100 - table of equivalents on back - possibly transition model with paper (edges + back) & painted (front) scales

Fowler
ModelTypeCommentsThumbnail
JuniorPocket Concentric long-scale

Exceptionally for Fowler circular rather than pocket-watch type - unusually serrated revolving discs - many gauge marks around outermost/peripheral ring on both sides​

Long ScalePocket-Watch Concentric long-scale - early

Serial No. 14075 stamped in bulls eye on back - two milled winders - many gauge marks around outermost/peripheral ring on both sides

MagnumPocket-Watch Concentric long-scale

Two milled winders - many gauge marks around outermost/peripheral ring - plain black back​

Type BPocket-Watch Textile - early

Two milled winders (one missing crown ring) - many textile-based gauge marks around outermost/peripheral ring - plain chrome back

Type E1Pocket-Watch Textile

Serial No. 4404 - two milled winders (one with crown ring) - many textile-based gauge marks around outermost/peripheral ring - table of weaving-related factors on back

Gamma
ModelTypeCommentsThumbnail
2503Budapest DarmstadtCompany founded in Hungary in 1920 but may have started with OEM rules from UK maker A.G. Thornton as the style of the pi & telltale 8-pointed star marks on the box with Gamma name & logo suggests it is an early Thornton/PIC-made rule.
Gebr. Wichmann
ModelTypeCommentsThumbnail
1919RDesktop Rietz

OEM by Nestler - cm scale in well of stock + hand-written list of formulas on back

431Mannheim

Model from the earliest known series​ - table of conversion factors on back

Geo. W. Richardson
ModelTypeCommentsThumbnail
1776Direct Reading Polymetric Rietz

Keyholes (top left & bottom right) are direct reading line-up points for a table of codes on the back. By aligning a chosen code in the keyhole the slide is automatically set for the chosen calculation. Provisional patent no. 1-31-11 on slide - full patents = 1911 US982876 & in 1912 US1021484 .

812Direct Reading Enhanced Mannheim

Keyholes (top left & bottom right) are direct reading line-up points for a table of codes on the back. By aligning a chosen code in the keyhole the slide is automatically set for the chosen calculation. Provisional patent no. 3-26-12 on cursor - full patents = 1911 US982876 & in 1912 US1021484 . ​

Slide Rule Model of 1917Desktop Artillery Range Finding

Robust military grade OEM for J. H. Weil & Co. - Trig scales are in Mils (6400 mils = 360 degrees)​

Goliardo
ModelTypeCommentsThumbnail
(NoName)Pocket Mannheim

Little known Italian maker/reseller

Gordon, A.M.
ModelTypeCommentsThumbnail
Scale of Power & SpeedShip design/constructionOne of a set of 4 such rules designed by Glaswegian Alexander Milne Gordon (1870’s-1922) M.I.N.A.
Graphic Calculator Co.
ModelTypeCommentsThumbnail
Foxboro Vortex Flowmeter Sizing GuidePipe Flow (steam & gas)Specially commissioned slide chart but with slide rule operations & cursor - front for steam - back for gas - table on front
Graphoplex
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(NoName) 615Pocket Rietz - early

Early because lacking model no. + red outline of logo​ - longer than usual for pocket - two open windows with cursor line in back

(NoName) 620Rietz - early

Early because milky white original plastic + lacking model no. + red outline of logo​ - two closed windows with cursor line in back + table of constants om back

1600School Rietz C.A.P.
1600School Rietz C.A.P. - blue bands

Grey plastic case denotes a later model - “easy reading” blue banding for A/B & C/D scales ​

1612Pocket Rietz - early & all black

one open window right with 1 hairline in back - black logo = early model

1614Demonstration School Log-Log

Does not have cm top edge scale on standard 25cm 1614

1614School Log-Log C.A.P.
1694Technical
16ooSchool Riez C.A.P. - early & all black

Note mixed alphanumeric 16oo model no. - layout different to standard/later 1600 Rietz - black logo = early model​

604Typography Cicero printing

No slide - Cicero (old French thumb unit of measure = 27.07mm) is a typographic unit similar to a pica but with 15th century origins​

612Pocket Rietz

one open window right with 1 hairline in back

615Pocket Rietz

Slightly longer than the 612 - one open window right with 1 hairline in back​

620 (ver. 5)Rietz

One closed window right with 1 hairline in back​

620 d (ver. 1)Rietz

Model no. on back of slide - one open window with cursor line in back on right​

630Geometre Surveying Topography - 400 g early

Missing model no. + table but one open window with cursor line in back on right

640Electro Log-Log

Retail stationer’s name Joseph Gilbert on back + one open window with 1 hairline ​in back

643Pocket Electro Log-Log

Name of NL company Ingersoll-Rand in well of stock - one open window right with 1 hairline in back

647Darmstadt

Unusual inclusion of AI scale ​

650Pocket Electro

§ scales = 2-part COS scale - unusually for Electro’s W & V scales on front face ​

680 STATOS Reinforced Concrete - System Lüthy/Nussbaum

Patented design (CH314378) by Peter Lüthy & Max Nussbaum - § scales for N = 10 - Co. name MONTEFERNO, Bodio (CH) in well & on back - table of constants on back

681 STATOSPocket Reinforced Concrete - System Lüthy/Nussbaum

Patented design (CH314378) by Peter Lüthy & Max Nussbaum - § scales for N = 10 - Co. name MONTEFERNO, Bodio (CH) & table of constants on back

690 aNeperlog log-log

Impressive layout of 26 scales - Neper or Np is a logarithmic unit of measurement of physical field & power quantities - comparable to ARISTO 0968

CALTEX Petroleum Rietz

Same model rebadged for TEXACO & ​CALCRUDE - red outline of logo = early - bizarre cursor design - °F & °C scales in well of stock - back of slide has American Petroleum Institute (API) crude oil gravity scales - table of constants + CALTEX logo on back

DYNSTAT Desktop Impact Testing

DYNSTAT is a mechanical impact/resilience testing method popular in Germany (DIN 53435) for testing small samples of plastic ​

EDF 355.145Electrical Power Cables

EDF = Electricitè de France - identical to model EDF 35 11 408 - table of values for single-phase lines in well of stock​ - table of maximum permissible intensity values on back

Gaz de France 65-TX-01Pocket Gas Pressure/Flow in Pipes & Ducts
KOH-I-NOOR 10020Technical

Part of series for Czech stationer KOH-I-NOOR - copy of model 1694​

Meteo No. 2Meteorology - early & all black

Simpler version of two Meteo models ​for weather forecasting - distance scales in both imperial & metric - black logo = early model

Panneau PublicitaeDemonstration/Display Log-Log

100% dummy - scale layout printed on sheet of plastic as shop window advertising item - also made half-size version​

REVACOHydralic/Pipes/Valves flow rates

Made for CONTROLEXACT (later version II for COMSIP AUTOMATION) - for calculating flow (liquid & gas) in valves & flowmeters - REVACO = registered trademark - unusual layout/design & striking cursor

REVACO IIHydralic/Pipes/Valves flow rates

Made for COMSIP AUTOMATION (original version for CONTROLEXACT) - for calculating flow (liquid & gas) in valves & flowmeters - REVACO = registered trademark - unusual layout/design & striking cursor

ROPLEXRietz

Designed for rapid & accurate calculating - circular but housed in square case - front & back shown as per instructions - slide also worked by metal wheel - table of gauge points in centre​

SHELLPocket Petroleum Central Heating Efficiency

Unique construction with slide being part of closed frame (no cursor) on back of stock​ - registered design commissioned by Shell Nederland Verkoopmaatschappij (SNV) - used by Heating Oil Inspectors with equipment for measuring CO2 levels, temperature & soot content of exhaust gasses in the flue - read more ...

SHELLPocket Petroleum Central Heating Efficiency - NL version

Unique construction with slide being part of closed frame (no cursor) on back of stock​ - registered design commissioned by Shell Nederland Verkoopmaatschappij (SNV) - used by Heating Oil Inspectors with equipment for measuring CO2 levels, temperature & soot content of exhaust gasses in the flue - read more ...

SHELL-MEX/BPPocklet Petroleum Stack-Loss

Shell-Mex & BP logo’s on back + one open window with 1 hairline in back - follow-on from earlier OEM Central Heating Efficiency model made for Shell in NL (SNV)​ - read more ...

THERMOCOAXMetrology Electro

Top 3 scales are constants for Chromel, Iron & Chromel/Alumel - bottom 4 scales are for Chromel/Alumel (but smaller range) & Platinum/Rhodium (3 different %‘s) - scales on front of slide are for 2 different voltages of electrical couplings ​- inch scale on back

Halden (Joseph)
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Calculex -1795APocket Eugene Dieztgen - Type 2

Yellow rear cursor glass stamped with the no. 45 suggests sold by Eugene Dieztgen

DafieldMonetary

Made by John Davis & Son - Patent No. GB227643 in well

Heath & Co
ModelTypeCommentsThumbnail
HezzanithCarmody Navigational Log-Log

Probably designed by Dr. Carbody but OEM (P1572) from Blundell Harling (box + insert & patented adjustment screws) - cm scale on back + unique table of half-versine or haversines - the table is vital when the distance between two points is < 400km

HezzanithEnhanced MannheimInch (32nds) & cm (mm) scales in well of stock - conversion tables on back
HezzanithNavigational Mannheim

Possibly Thornton-made (similar to PIC 3654) - reduction scale (not Haversines) by Captain Charles Le Patourel in well of stock for correcting degrees above horizon when a star transcends its meridian - Le Patourel compiled tables of nautical data also on back

Hemmi
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101ADemonstration Enhanced Mannheim

Classroom version for models 40RK & 43A - Sun was added later as company logo ​

279Desktop Expert Mechanical Engineer

Desktop version of 25cm model 259​

30Lilliput Enhannced Mannheim

Sale item​

70Desktop Improved Rietz

Also sold as Tamaya 4480 ​- table of conversion factors on back

P281 AhrendDemonstration Rietz

Probably locally made for Dutch office supplies company AHREND (still operating) as promotional item ​- Instruction rule for model P280/P281 - Rietz layout but all scales on front face

Hexadaisy Products
ModelTypeCommentsThumbnail
HEXADAISYHexadecimal calculator for computer programmersCopyright A695383 held by Erich A. Pfeiffer – probably called & trademarked “HEXADAISY” because it looks like a member of the Aster family of flowering plants
HEXCO Inc.
ModelTypeCommentsThumbnail
HEX adderHexadecimal slide adder for computer programmers

Registered design - company started by ex-IBM system engineers Tom & Linda Tarrant - catchy company slogan: “IBM 360 Programmers without 16 fingers ?” - read more ...

Hicks J.J.
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Pilot Balloon Mark IDesktop Meteorology poly-slide (2)

Meteorological Office (MO) No. 676/38 - innovatively two slides can be locked together & act as one or when unlocked, move independently BUT even when unlocked, if top slide is moved it takes bottom one with it.

HONO
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300 No. 1Rietz-like

All scales on front face - FAé-LuM on back refers = Force Aérienne–Luchtmacht i.e. OEM model for Belgium Air Force (source: Ronald van Riet) - HSB on back possibly company logo

Hope Slide Rule Mfg. Co.
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51Enhanced Mannheim

Of late Hope considered a manufacturer rather than a reseller​

Inglis
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FlashBank Interest poly-slide (4) calculator

Hybrid ready reckoner/tabular calculator for calculating bank interest due on deposits, discounting bills or prepayment of calls for amounts between GBP 10 to GBP 1000 - read more ...

FlashPocket Engineer's poly-slide (2) calculator

Hybrid ready reckoner/tabular calculator for machinery & other engineering related conversions & problems - read more ...

FlashSquare and Cubic poly-slide (4) calculator

Hybrid ready reckoner/tabular calculator for calculating square areas & cubic volumes - left-hand page of scales for calculating (imperial only) in feet and inches up to 20 sq. feet & 100 cubic feet - right-hand page of scales is for calculating (imperial & metric) in yards, feet or inches up to 100 sq. yards & 100.000 cubic yards - read more ...

FlashUniversal poly-slide (4) calculator

Hybrid ready reckoner/tabular calcuator for a wide variety of calculations including imperial based units - read more ...

Internationaler Tabellenverlag (ITAB)
ModelTypeCommentsThumbnail
KalksandsteinPocket Sand-lime bricksFor calculating required thermal insulation of house built with sand-lime bricks - unique magnetised slide - window in back of stock for reading off CI scale on back of slide
J. A. Nicholl & Co.
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Mark VI Desktop Artillery for Indirect Fire

Serial no. = 48 - called Apparatus for the Observation of Fire was intended for use by lance-corporals & corporals - issued by Min. of Defence

J.H. Steward Ltd.
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(NoName) Pocket Joint Round-hinged English Sector

Used with a set of dividers - OEM made (possibly by Jacob & Halse/Abraham group) but pre 1913 when Steward became a Ltd. - read more ...

(NoName)Pocket Rectangular Protractor/Diagonal Scale - imperial

0-360 degree model OEM made but pre 1913 when Steward became a Ltd. - read more ...

Motor TransportMilitary Vehicle Logistics & Supply

OEM made but post 1913 when Steward became a Ltd. - earlier version known as Vee Tee Meter - VEH = no. of vehicles - V.T.M. = Vehicles To the Mile -  M.I.H. = Miles In an Hour or mph - read more ...

Jackson Brothers Ltd.
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GravetMannheimLittle known maker from Leeds, UK
John Davis & Son (Derby) Ltd
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(NoName)Student Mannheim

Made by Dennert & Pape: no steel back, 4 horizontal slits in well of stock, veneers fixed by 6 screws, early D&P pi gauge mark - double bevelled edge model + paper scale for conversion factors on back

AutocratMannheim with trig scales

“British Made” - steel back + paper table of conversion factors

CelluloidMannheim with trig scales

Made by Dennert & Pape: no steel back, early D&P pi gauge mark + extension of inch scale (10-20) in well of stock + 06 & D.R.P. No 126439 stamped in well of stock

CelluloidMannheim with trig scales - early

Made by Dennert & Pape: no steel back, 4 horizontal slits in well of stock, no pi gauge mark - railway track scales + extension of inch scale (10-20) in well of stock + John Davis cardboard enclosure for conversion factors, etc

DemocratDesktop Mannheim with trig scales

15” version of Autocrat model with extension of cm scale (16-32) in well of stock. “British Made” - steel back + paper table of conversion factors

DubilierCapacitance Electronic poly-slide (2)

Made by A.G. Thornton: design copyrighted by Philip Ray Coursey whilst working for Dubilier Condenser Company - JOHN DAVIS & SON Ltd printed on the back and MADE IN ENGLAND in well of stock

DurocratDesktop Mannhiem

Unmarked - cm scale extension + 6 slits in well of stock - L scale reversed

GliderRietz

Glider name comes from slide-long slotted metal patented (GB232037 - L.E. Edwards) tensioning spring for “automatic” smooth sliding - steel back + paper table of conversion factors

John Rabone & Sons
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Carpenter Timber No. 2379 Pocket Joint 4-fold Old Arched-hinged Coggeshall

D Girt line = 4-40 + two-entry ½ to ¼ scale table & 12-18 “Pence per Load” table (split over 2 legs) on front

Carpenter Timber No. 2423Joint 2-fold Vulcan-hinged Coggeshall

D Girt line = 4-40 with Vulcan logo & design lozenge for 1869 + two-entry ¼ to ½ scale table on front + ¾-length E & M scales (split over 2 legs) on back

Jorgensen (Ole)
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7888 International Circle Pencil Cup/Desk Tidy Time Converter

Red with two black & one red rotating ring - made in Hong Kong

BulkoilPencil Cup/Desk Tidy Metric Converter

Black with two rotating rings - made in Denmark

CCWPencil Cup/Desk Tidy Basic

CCW = original Creative Workshop Inc. version - black with four grey metal rotating rings - made in Denmark

Control Data Universal CirclePencil Cup/Desk Tidy Basic

Black with two white & two grey rotating rings - made in Denmark

Kemigravyr AB
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M 3134-701 Aerial Photography

Made for Swedish Air Force​ (coat of arms top left)

Keuffel & Esser
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4051Desktop Enhanced Mannheim

Serial no. 322 + 5 adjustment screws & conversion table on back

4080-5Desktop Decitrig Log-Log

Serial no. 445698

4081-5Desktop Decitrig Log-Log

Serial no. 902506

N-4053-5 Desktop Polyphase Enhanced Mannheim

N prefix for new version + serial no. 740727 + 5 adjustment screws & conversion table on back

N-4096Desktop Merchants' Business

N prefix for new version + serial no. 699855 + stripped back scale layout for just x, ÷ & proportions + 5 adjustment screws & conversion table on back​ + with the lid open can be used in box!

N-4101 Desktop Stadia Surveying Topography

N prefix for new version + serial no. 106473 + 5 adjustment screws & conversion table on back

Kingson
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Pocket CalculatorSlide Adder

For adding/subtracting - table of decimal equivalents under subtraction section but otherwise blatant Hong Kong copy of Addiator ARITHMA 

Klawun, Joe
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10001 Ü (F-C 4/22)Desktop Business

OEM version made by Faber-Castell - British pre-decimal

16 C (F-C 67/91)Pocket Enhanced Mannheim

OEM version made by Faber-Castell

Koch, Huxhold & Hannemann
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1050Desktop Rietz

On balance probably KHH-made (some but not all of typical KHH traits) but mysteriously “Sistema Rietz” (Spanish) in gold lettering on slipcase & stamped in well of stock - paper data slip missing from back​

L&C Hardtmuth / Classic
ModelTypeCommentsThumbnail
Series IMannheimUnusually for any maker top edge is straight & bottom edge is bevelled - bottom bevelled cm edge scale upside down + table of constants on back
Series IPocket MannheimTop bevelled edge inch scale upside down + table of constants on back
Series IILog-LogBottom edge cm scale upside down + table of constants on back
Series IIPocket Log-Log

Bottom edge cm scale upside down + table of constants on back

Series IIIPocket MannheimBottom bevelled edge cm scale upside down + unit of measure extension (inch) scale in well of stock + table of timber constants on back
Series IVMannheim + TrigStrange/unusual scale layout - bottom bevelled edge cm scale upside down + table of constants on back
Series VLog-Log extra

Series model no. strangely left off - unusual choice of scales - bottom bevelled edge cm scale upside down + table of constants on back

Series VIRetail/MonetaryBased on patent GB621133 (A.W. Parkes) for pre-decimal pounds sterling + bottom bevelled edge cm scale upside down
Lawrence Engineering Services
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10-B blueEnhanced Mannheim without Trig scales

Monchrome blue version of standard 10-B with conversion tables on back

10-B DeLuxeEnhanced Mannheim without Trig scalesDeLuxe = magnifying cursor. Conversion tables on back of rule
10-B DeLuxeHow To Use It bookAuthors Sommers/Drell/Wallschlaeger - published by Grosset & Dunlap (dirty orange & black) and Wilcox & Follett Co.(dark-green & gold)
10-B OEMGENE LOEWY Enhanced Mannheim without Trig scalesname on enevelope not rule
10-B OEMLARCH Enhanced Mannheim without Trig scalesname on enevlope not rule
10-B originalEnhanced Mannheim without Trig scalesEarly 25¢ slide rule
10-B standardEnhanced Mannheim without Trig scalesConversion tables on back
10-CEngraver's and Photographer's Proportion CalculatorFor area % up & down scaling
10-DLumber Calculator - basic versionFor lumber volume in board feet
10-D0Lumber CalculatorFor lumber volume in board feet
10-FPricing and Inventory RuleFor discount or profit margin mark-up per gross/dozen/each in $‘s
10-GCutting Speed CalculatorFor recommended cutting speed in f.p.m for given drill speed & size
10-IModel Builder's Slide RuleFor calculating the scaled down dimensions (various railway gauge sizes) for replica scaled models of railroads/trains
10-NPrinter's Proportion RuleFor moving between inches & picas when printing/publishing
12-HCopyfitter printingFor font size and letter/word/line spacing in points and picas - layout © Owen T. Taylor
12-JPro-RaterFor calculating days between two dates & pro-rata premium/days
250-BTEnhanced MannheimConversion tables on back
250-BT OEMCHARVOZ-ROOS SR31 Enhanced MannheimConversion tables on back
250-BT OEMDU PONT Enhanced MannheimConversion tables on back
250-BT OEMLIETZ 2974N Enhanced MannheimConversion tables on back
250-BT OEMUS NAVY Enhanced MannheimConversion & gauge marks tables on back
250-VEnhanced MannheimMarketed as a "Professional Slide Rule" - conversion tables on back
6-OpPocket Flashrule for GE or Westinghouse flash bulbsPhotography tips printed on back
6-OwPocket Flashrule for WABASH flash bulbsPhotography tips printed on back
8-AMannheimConversion table printed on back - Wabash made
8-BEnhanced Mannheim without Trig scalesConversion table printed on back - Wabash made
8-B OEMANCO Enhanced Mannheim without Trig scalesPaper table of decimal equivalents on back
8-B OEMDU MONT Enhanced Mannheim without Trig scales
8-LCopper Wire SelectorFor minimum wire size/volt (440/220/110) in A.W.G. - conversion tables on back
8-LCopper Wire Selector - basic Cedar Valley versionFor minimum wire size/volt (440/220/110) in A.W.G
9-KMusic TransposerFor constructing chords in any key & transposing one key to any other
B.F. GrizzleGas Displacement Meter Calculator

For calculating gas rates through displacement meters @ various pressures - layout © B.F. Grizzle

B.F. GrizzleGas Low Pressure Line Flow Capacity Slide Rule For calculating open flow rates using pilot tube pressure readings - layout © B.F. Grizzle based on Spitzglass’ formula
B.F. GrizzleGas Pipe LineFor calculating the gas flow capacity/hour through a pipe of a given diameter - layout © B.F. Grizzle based on Panhandle Eastern Pipe Line formula
B.F. GrizzlePipe Open Flow Capacity

For calculating open flow rates based on pilot tube pressure readings & using Reid’s formula for pipe profiles - layout © B.F. Grizzle

B.F. GrizzlePipe Orifice Meter Calculating Rule For calculating the size of conduit restriction needed to create a required pressure drop - layout © B.F. Grizzle
B.F. GrizzleWater Line CapacityFor calculating the friction loss in a section of pipe & head loss for a given pipe diameter, length & flow - layout © B.F. Grizzle based on Hazen–Williams equation
Canadian Radium & UraniumGamma-Ray RadiographicFor commercial (steel or alloys) rather than medical use - for determining the appropriate exposure times for radiographic images involving radium-226 sources
CaprockConcrete Quantity CalculatorFor calculating cubic yards of concrete needed for or in a wall of certain dimensions
Code-MakerPocket (boxed pair)Rules carry an advertisement for Robin Company, Chicago
Code-MakerPocket BeichPart of loyalty scheme for WHIZZ chocolate bars
Code-MakerPocket Dick TracyBecause of the Dick Tracy connection presumably marketed in cooperation with the “Chicago Tribune New York News Syndicate”
Fun IncorporatedPocket Poker Meter
Ideas UnlimitedPoker Meter“Statham Laboratories Inc.” + address stamped on back & listed on instructions
MadisonCutting Speed CalculatorFor calculating the drill and cutting speed for a given cutting diameter - extra tables on back
Miller MotorAir and Hydraulic Cylinder CalculatorFor calculating air & hydraulic cylinder values such such as thrusts, bores, areas displacements, etc - conversion tables on back
MITAntenna radar beam patternsClassified during WWII by UK & US governments - design based on research by Roy C. Spencer (RSC) for calculating radar antenna beam patterns, beam width, gain, etc
Murphy & MurphyConcrete Quantity CalculatorFor calculating cubic yards of concrete needed for or in a wall of certain dimensions
PioneerTV coverage calculatorUV/M-DB conversion scale on back - layout © J.B. Epperson
Plaza ExpressTraffic Manager's

For for checking freight shipping charges or shipping rates or shipping truck/carload breaking points & calculating storage costs - layout © M.T. Brockman

RCAF.M. coverage calculatorFor estimating coverage of FM radio stations according to the type of RCA antennae
Taylor PublishingCopyfitter printingFor font size & letter/word/line spacing in points & picas (copy 12-H) - layout © Owen T. Taylor
TenbrookL.P. GasFor calculating the temperature correction (°F) needed when making bulk deliveries of Propane
ThomasMusic Composition & Transposition

For composing, transposing or creating harmonies - layout © Thomas

Tokheim 92"K" Factor fuel oil supply calculator

Made for Tokheim Oil Tank & Pump Corp. - for calculating supply requirements of household heating/fuel oil - K factor is a way of showing (gallons/degree day) how fast a consumer uses fuel (analogy = miles/gallon in a car)

US Army (DeYOE)Artillery Range FindingCalled a “Graphic Table” by the US military.
US Aviation UnderwritersInsurance actuarialTable on back for cancellation ratio’s/days - layout © Albert J. Smith
Le Girondin - ELPE
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TOTALISSlide Adder

Marketed for pre-Euro (2000) calculating in French Francs (Fr) & Centimes ​

Leningrad Factory
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(NoName)Desktop Military Artillery Range Finding

Made in the style of earlier Russian Prometei-made military/pilot slide rules. Intriguingly the military RWTL-2 labelling (in German) on the box stands for Rockets and Weapons Storage - 2 @ Hennersdorfer Heide, Lower Austria. ​

LFAI - Leningrad
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(NoName)Desktop Rietz

ROCT (GOST) Russian State Standard No. = 5161-57 + conversion factors & formulas on back​

(NoName)Rietz

ROCT (GOST) Russian State Standard No. = 5161-49 + conversion factors & formulas on back

1cPocket Enhanced Mannheim

ROCT (GOST) Russian State Standard No. = 5161-57

Lines Bros Ltd / Tri-ang
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C276 Scalextric Speed ComputerTime-Speed-Distance calculator

Scalextrix model car racing sets (now distributed by Hornby) date from 1950s - calculator gives scaled (32:1) equivalent MPH or KPH for distances travelled for clocked no. of seconds - track slot lengths/type in cm for finding total track length on back

LINEX
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(NoName)Enhanced Mannheim

Two spring-loaded ball bearings in top side of well to tension slide. Rad more ...

1253Pocket Mannheim

Umarked

LOGA
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K150dPocket Business/Technical Rietz-like

“d” model no. suffix = German version - unusually separate slide for each side of closed frame - front for Business & back for Technical use - many gauge points above & below slide on front face + on cursor - adjoined CI/% = ½ length scales - table of gauge points abbreviations in well on front + table of constants in well on back ​- see 30cm version

K300dBusiness/Technical

“d” model no. suffix = German version - unusually separate slide for each side of closed frame - front for Business & back for Technical use - many gauge points above & below slide on front face + on cursor - adjoined CI/%/§ on front = mini scales - table of gauge points abbreviations in well on front - % scale on back = 2-part - see pocket version

MARC A.A.F. / MINERVA
ModelTypeCommentsThumbnail
Minerva No. 5 ElectricienPocket ElectroV & W scales in well of stock - from short lived MARC-Minerva collaboration before Minerva started importing ARISTO slide rules
No. 2 MannheimPocket MannheimInch scale & André et Yernaux, Courcelles on back
No. 2 MannheimPocket Mannheim - earlyEarly cursor & overall 5cm shorter than later versions - Cement-Ijzerfabriek “Wittenburg”, Amsterdam stamped in well - inch scale on back
No. 4 Sinus et TangentePocket Enhanced Mannheim
No. 5 ElectricienPocket ElectroV & W scales in well of stock - later plastic rather than celluloid stock
No. 6 RietzPocket Rietz
Master
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BusinessSlide Adder

Maker is Liege, Belgium based (no connection to US based Master Electric maker) - “man in cap” 1 of 3 company logo’s - addition only

Maurice Damien
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Universal Rietz (Type 4)

Unusually all-metal for a European maker - table of conversion factors in German on back + company logo = dam - one only 3 known linear models

Mear & Co., M.H.
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Domestic Heating Calculator - model 4 imperialHeating installation design for traditional houses & bungalows - earlySt. Helen’s Gate address - determines the heating requirements for older norms/types of domestic premises & also the sizes of all the equipment needed for ‘the installation”
Domestic Heating Calculator - model 9 metric Heating installation design for houses & bungalowsDetermines the heating requirements for older norms/types of domestic premises & also the sizes of all the equipment needed for ‘the installation”
Gas Flow Calculator - model 3High or low pressure gas flow in steel pipesSingle-sided - Model 3 = improved model based on Colebrook-White formula (replaced Lacey’s coefficients for such calculations)
Gommer Comprehensive Conversion CalculatorConversionSpecial commission for J. Gommer, Voorburg, NL - 2nd disc with multiple look-up windows on front - cursor on back
Orifice & Nozzle Flow CalculatorPipe Flow (liquids/gases/steam) For calculating flow in pipes for various types of orifice plates & nozzles according to British Standard 1042 - front for results in volume or mass - back for flow coefficients
Smith Conversion CalculatorConversionSpecial commission for A O Smith corp. London - 2nd disc with multiple look-up windows on front
SRA Helical Coil Spring Calculator - metricDesigning tension or compression in helical springsSpecial commission for Spring Research Association (SRA) - for designing helical soil springs according to BS 1726 part 1 - will handle springs made from round, square or rectangular section wire
Warm Air Heating Calculator - model 2 imperialWarm air domestic & small installations Divided into sections each dealing with a particular aspect of the overall calculation
Water Flow Calculator - model 3 imperialFlow rates through pipes, ducts & sewersFront for determining flow of water through pipes & ducts with circular cross-section according to Moody’s coefficients - back for determining flow of water in large open channels of any cross-section (Manning formula)
MEISSNER KG
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(NoName)Rietz

Later versions followed - table of conversion factors on back

Rietz-Arcus 1731543Rietz-likeMissing usual K & A/B scales of a Rietz layout + unusually for a Rietz all scales on front face - “1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality”
TRIMunknownUnusual choice of scales & layout -“1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” + heated stamped “93” on back
Morin, Henri
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Regle pour Essais des Duretes des Metalix Set for testing metal hardnessTable of conversion factors on back + 12 varying steel weights + set of test slides (wrapped) + rubber + heavy sprung testing piston/hammer 
Nestler
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0203 AlphaDemonstration Rietz

Instruction rule for model 0251 - Rietz layout but all scales on front face ​

0215Desktop Darmstadt 360°

tables of conversion factors on back

0235Desktop Rietz

tables of conversion factors on back

0440Polymath Reinforced Concrete - System Maarschalk

Sales item​

18Desktop Enhanced Mannheim

cm scale in well of stock + tables of conversion factors on back

21aDesktop Darmstadt 360°

cm scale in well of stock + table of conversion factors on back

23a (A/R)Desktop Rietz - late

Unusual scale length​ - tables of conversion factors on back

24Desktop Rietz

cm scale in well of stock + tables of conversion factors on back - ex Shell (B.P.M.)

24bDesktop Extra Rietz

NOT demonstation model but engine-divided (Nestler only maker for desktops > 50cm) - read more ....​

24RDesktop Rietz - late

cm scale in well of stock + tables of conversion factors on back

27Desktop Precision long-scale

cm scale in well of stock+ tables of conversion factors on back - long scales (folded @ Pi) & desktop model meant accuarcy of 0.03%

28aDesktop Universal Topography 400g

tables of conversion factors on back - later replaced by 0286 Geometer

40aDesktop Business - late

Unusual scale layout + British pound sterling (£ s d) scales on back of slide + conversion tables on back

45Cylinder long-scale

Effective scale length = 12.5m​

Norden
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(NoName) Pocket Mannheim

NIFE (Swedish company set up by Georg Vogel to manufacture optical products) logo stamped on back - company name derived from battery components Nickel (Ni) and Iron (Fe)

(NoName)Pocket Rietz

Unusual layout of the scales

2/48DarmstadtAppears well made
NORMA-Mechanik
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Gambrinus 100Pocket Beer Brewing

Gambrinus = European folklore entity & icon for beer & brewing - easier to use than contemporary beer brewing rules from F-C, Nestler, etc + company name & logo for “Ziemann Brauerei” on back

Grafia 190Basic PaperHanging/floating cursor + many gauge marks + many paper/graphics industry specific factors such as datum marks for DIN sizes
Mekuria 190Business

Inner ring has many gauge marks for imperial-based conversions

Simplex 100Pocket Basic

Too basic to have the typical hanging/floating cursor + simple raised lug for moving inner disc ​

Orgelbau-Fachverlag
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(NoName)Desktop Music Organ Pipes - System Rensch

Made for German specialist publisher: Oreglbau-Fachverlag. For scaling organ pipes (wood metal flues & reeds) - orignal limited OEM higher-quality version by F-C. Table of frequencies on back.

Otto Meuter Rechenmaschinenfabrik
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PRODUXSlide Adder - gold/black

Being a “Lilliput model” means adder bars are exposed when calculating - no display clear/reset function​

Posterijen, Telegrafie en Telefonie (PTT)
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CWP 11Cable Radio - signal loss in dBWell of stock + slide both shaped as isosceles trapeziums (CWP = centrale werkplaats/central workshop)
Prometheus/Prometei/Prometejs - Leningrad
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Model 1Rietz - early

Prometheus = English version of Russian company names + hand-written serial no. = 7435 (also on back of slide) + nothing in well of stock = early model + conversion factors & formulas on back ​

Refinery Supply Co.
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AC-ME Pocket CalculatorPetroleum Gas Flows for Orifice MetersOEM by Nestler (style of Pi + MADE IN GERMANY on back) + AC-ME = Ac-curate Me-asuremet Precision Instruments (? designers) + version also made by Pickett (1080-T)
Reiss
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(NoName - ver. 1)Artillery Range FindingMaybe VEB MANTISSA made or transition model because of typical MANTISSA case & cursor
(NoName ver. 2)Artillery Range FindingEarlier (or later) ver. 1 is open frame & has a cm bevelled edge scale but no extra D scale on back of stock.
(NoName)Artillery

For calculating the amount of charge needed/range in meters for various types of charge - has no slide!

(NoName)Dummy

Showroom model (slide fixed) or possibly representatives sample

(NoName)RietzCostly “over engineered” construction to accommodate bevelled edge cm scale & supplementary mini-cursor
3223Progress log-logProgress type = refinement of two earlier Robert Reiss’ extended scale ideas - well-engineered slide rule with unusual scale layout
Rijnja, P.
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BeamsWooden Floor & Ceiling Beams - System Van Gerven

Tailor-made blank & cursor Hans Seehase but Rijnja added the scales - in this design Van Gerven included adjutment for beams bowing - table of building construction standard reference values in well of stock

Beams - basicPocket Wooden Floor & Ceiling beams - System Van Gerven

Tailor-made blank & cursor by Hans Seehase but Rijnja added the scales - table of building construction standard reference values on back

ConcreteReinforced Concrete Floors - System J.L.H. Strackee poly-slide (2)

Tailor-made blanks supplied by Hans Seehase but Rijnja added the scales

Robson & Co., F.
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(NoName)Desktop Steel Weight Calculator - imperial

Little known UK (Newcastle on Tyne) instrument maker

Scientific Publishing Co.
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Type TPocket-Watch Textile

Transition model as company name changes to Fowler - yellow lens face - two milled winders (one with crown ring) - table of weaving-related values on front face + table of weaving-related factors on back​

Seehase, Dr. Ing.
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(NoName)Pocket Mannheim

Model often used as a promotional gift/giveaway with a company name/logo on the back

ConversionPocket English and German MeauresIncorporates 34 different imperial to metric conversion “gauge marks/factors
System SchirdewanTextile

Used in a leading textile factory of the day Scherg (Brasov, Romania) + tables of constants on back - read more ...

Seger
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No. 52DarmstadtName “Seger” & “MADE IN NORWAY” blind stamped in well of stock + indistinct blind date-stamp on back = lookalike Norwegian-made copy of Faber-Castell 111/54?
Service Slide Rule Co.
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ElectroLog-LogPS gauge mark wrong 746 = HP + conversion factors on back
ReedElectronic Engineers

D/L (Diameter to Length) Nagaoka coefficient scale in well + many innovative gauge marks - read more ...

Servo Calculator Co.
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Boonshaft & FuchsDesktop Frequency Response

After preloading 11 of 25 removeable slides the chosen scale layout can calculate a direct reading of amplitude ratio & phase v/s frequency of all terms in a complex transfer function for each of the 10 transfer function slides loaded

SIMI
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154/47DarmstadtName “SIMI MALMÓ” & “MADE IN SWEDEN” printed in well of stock & on box = lookalike Swedish-made copy of Faber-Castell 1/54 (even the model numbering!) but not of the same quality
Slide Rule and Scale Engineering Co.
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KoehringConcrete Quantity CalculatorFor calculating no. of batches need to concrete over a specific area when using particular models of Koehring & KwikMix pavers/mixers - design by G.L. Lockhart & copyrighted 1948
REDI-MIXCircular Construction CU.YD. / Concrete CalculatorUnusal duplex construction with two (front & back) closed frame slides - copyrighted design + patent applied for
Victor L. PhillipsConcrete Quantities and AreasCalculator for computing imperial concrete quantaties & areas with company details on back - copyrighted design
W.H. PipkornBrick & Tile

1940 copyrighted design for determining bricks or tiles (also other masonary units) needed/used to build a wall of given dimensions (l x h) - tables on back show various types & sizes of masonry units + wastage  

SPZ - Voronezh
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NL-10mAviation Flight Computer

Identical model made by Russian LFAI factory​

Staedtler-MARS
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544 28Log-logOEM Nestler Multimath Duplex 0292
544 ATechnical

Probably made by Fujj (F-100) - unusual choice of scales & layout common to Japanese makers - possibly retailed as a package with OHP version

544 A AVDemonstration OHP Technical

Unusual choice of scales & layout - only other known examples are from Japanese makers - overhead projector version for model 544 A

Stanley (London)
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GoochDesktop Gauge for Centering poly-slide (2)

Invented & patented (GB189313940 - 1894) by Charles Gooch as an impoved gauge for centering & mounting photographic prints et al - the 2nd slide is attached on top of the slide in the stock by means of a metal sleeve/clamp ​

M3686Electro

For Electrical or Mechanical Engineers - V & W scales in well of stock - table of conversion factors on back

M3689 Student Mannheim

Cheaper version (celluloid facings only one front face) of M3656 - MADE IN ENGLAND and STANLEY LONDON stamped on slide

Pilot Balloon Mark IIDesktop Meteorology

Meteorological Office (MO) No. 1979/43 - possibly made for Stanley by J.J. Hicks or A.G. Thornton - adoption of standard rates of ascent removed need for Mark I poly-slide (2) but 4th cursor needed for “tail method”

Professor Fuller's Type 1 Calculating Slide Scale K3614Desktop helical long-scale

Long Fuller Serial No. 4869 with conversion tables, natural sines and Birmingham Wire Gauge on inner fixed cylinder

W.H. GlaserDesktop Textile Converion poly-slide (2)

Unusual fixed cursor extending the range of a relatively short scale length - read more ...

Stanley Rule & Level Co. (USA)
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Carpenter Timber No. 12Joint 2-fold Old Arched-hinged Coggeshall

D Girt line = 4-40 + four-entry ¼ to INCH scale table on front + ¾-length E & M scales (split over 2 legs) on back

Carpenter Timber No. 46Joint 2-fold Large Plate-hinged Coggeshall

No D Girt line - unbranded but font & model numbering identical to Stanley (USA) but mysteriously only has B,C scales on front + ¾-length E & M scales (split over 2 legs) on back - or is it a later copy/forgery?

Sterling Plastics (USA)
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(NoName)Pocket Octal/Hexadecimal calculator for computer programmers

Based on 1973 American patent US3716186A (Kent B. Comfort) - promotional give-away for Environmental Dynamics Inc. (EDI)

587Pocket Enhanced Mannheim

Typical raised moulded back of stock

Dial-A-MaticPascal Adder for simple arithmetic

4 dial design based on 1957 patent (US2797047) by Otto Springfield ​

PrecisionEnhanced Mannheim

Typical raised braces & pillar supports part of the stock

Stevens Engineering Co.
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Rally Indicator - model 25 Time-Speed-Distance rallying calculator California based maker specialising in rallying equipment, clocks, etc - road rallying tool popular in North America - long metal arm = “T” + 2 short metal arms = “E” & “M” - imperial/metric conversion table on back
Sunrise - Moscow
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Krougovaia Logarifmioueskaia KL-1Pocket Basic

Model name = Circular logarithmic in Russian + black dotted winder for A & C scales wheras red dotted winder moves both pointers simultaneously ​

Systeem Matthijssen
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370DesktopUse/purpose of the many gauge marks is unknown - SR built into desktop stand for Nederlandse Kabelfabriek (NKF - Dutch cable factory in Delft)
386Desktop Technical

Use/purpose of the many gauge marks & scales is unknown - SR built into desktop stand

Tavernier-Gravet
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(NoName)Rietz

Left & right small window with cursor lines in back - paper table on back missing​

Tecnostyl
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41/RPocket Rietz

Promotional gift from office furniture supplier: ASPA ​

CalcolatorBasic

Novel graduated ring of raised marks to aid lining-up/turning inner disc ​

Thomas Hart Ltd.
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Lambeth Basic horsepower calculator for steam enginesPromotional giveaway (possibly part of a series) for finding the HP needed for steam engines driving a line shafting set-up in a factory - design possibly by Pickworth - table on back for max HP for ropes of a given diameter/weight
Thomlinson
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Equivalent Paper Slide Scale"pocket" poly-slide (2)Extensively used in paper making industry - uneven alignment of letters and numbers
Thornton A.G. / P.I.C. / British
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A.G. (NoName)Desktop "prototype"

Unbranded but attributable to Thornton (horizontal/flat diamond box identification marks & reversed bottom edge scale) - traditional B scale replaced by upward pointing arrow - read more ...

A.G. (NoName)Poly-slide (2) Steel

Possibly made by D&P (Pi symbol) for naval steel shipbuilding where all weights in construction are recorded to calculate final displacement.

A.G. 0552/1448Time-Speed-Distance calculator

Later version of model Pattern 1448 - all time related scales in black & all speed/distance related scales in red - Difference in Longitude (D Long) scale on back for converting between degrees and nautical miles

A.G. D6957Improved Perry Log-Log

Made by Nestler (German silver screws + DRGM 164885 in well) - top edge 1/50ths Inch scale for engine indicator diagrams - bottom Perry scale (0.91-10-4) patented (GB190123236) = reciprocal variant of LL (e-1) - Inch scale in well of stock - A.G. Thornton Manchester + conversion tables on back

A.G. English ElectricLilliput A.C. Power Factor Electro

Made for English Electric Co. B1 & C1 Power Factor scales (A.J. Riches patent GB520442) on back of slide easily mistaken for reciprocal BI & CI scales - read more ...

A.G. Pattern 1435Time-Speed-Distance calculator

Upward arrow preceding model no. on front face is UK government mark - all time related scales in black & all speed/distance related scales in red - identical scale layout as Pattern 1448 BUT without Difference in Longitude (D Long) scale on back of slide

British AD 050School Differential Log-Log

Extra Thornton patented differential Trig scales ≡ to model P271 - superseded by model AD 150

British AD 060Standard

≡ to model P281

British AD 070Rietz

Rietz type without Trig scales

British AD 150Log-Log

Later replacement for model AD050

British P221Differential Comprehensive Log-Log

Extra Thornton patented differential Trig scales & Vector analysis scales - superseded by model AA 010

British P271School Differential Log-Log

Extra Thornton patented differential Trig scales - superseded by model AD 050

British P281School Standard

superseded by model AD 060

PIC 111/PC 8Differential Rietz

Rietz type without Trig scales but with extra Thornton patented differential Trig scales - conversion tables on back

PIC 112Desktop Differential Rietz

Rietz type without Trig scales but with extra Thornton patented differential Trig scales - conversion tables on back

PIC 121/PC 18Differential Log-Log

Extra Thornton patented differential Trig scales & Vector analysis scale - conversion tables on back

PIC 122Desktop Differential Log-Log

Extra Thornton patented differential Trig scales - conversion tables on back

PIC 131Differential Electro

Extra Thornton patented differential Trig scales - V & W scales in well of stock (metal well cursor) - conversion tables on back

PIC 131/PC 18Differential Electro

Extra Thornton patented differential Trig scales & Vector analysis scale - V & W scales in well of stock (plastic well cursor) - conversion tables on back

PIC 141A.C. Electricians Electro

Front face has Trig scales, rapid √squares of 2 numbers scale & temperature resistant (°C & °F) copper scales - angle to Log conversion scale on bottom edge - conversion tables on back

PIC 144A.C. Electricians Electro

Front face has Trig scales, rapid √squares of 2 numbers scale & temperature resistant (°C & °F) copper scales - angle to Log conversion scale on bottom edge - conversion tables on back

PIC 163Clementson Water Pipe Sizing

Bottom “duo” scale for pipe diameters according to Rietschel formula (in black) & according to Meier formula (in red) - table on back for friction equivalents in various fittings

PIC 221Differential Comprehensive Log-Log

Extra Thornton patented differential Trig scales & Vector analysis scales - superseded by models P221 & AA 010

PIC 241Differential Log-Log

Extra Thornton patented differential Trig scales - identical to model no. 271

PIC 271School Differential Log-Log

Made for Lennig Chemicals Ltd before relocating to Croydon, Surrey in 1968 - extra Thornton patented differential Trig scales - claim SR made from “high impact acrylic oroglas t”

PIC F 3649Log-Log

“F” model no. prefix = mahogany - mini resistance of copper wire scale for temperature variations on back of slide - conversion table on back

PIC F 3651Desktop Electrical & Mechanical Engineer Electro

V & W scales in well of stock - conversion tables on back of stock

PIC F 3654Mannheim

Mini resistance of copper wire scale for temperature variations on back of slide - conversion tables on back

PIC F 3658School Mannheim

wooden back

PIC F 3756Desktop Mannheim

conversion tables on back

PIC F 4865Engineer Commerce Electro

V & W scales in well of stock - mini Copper resistance scale on back of slide - conversion tables on back of stock

PIC JuniorSchool Mannheim

wooden back

PIC P251Standard

“P” prefix = plastic - oddball PIC

PIC Pattern 1448Time-Speed-Distance calculator

Upward arrow preceding model no. on front face is UK government mark - all time related scales in black & all speed/distance related scales in red - Difference in Longitude (D Long) scale on back of slide for converting between degrees and nautical miles

PIC Rule SlideMilitary Gunnery Royal Artillery

Extra gunnery gauge marks - typical 2 cursors (in case 1 gets lost!) for military version

PIC StandardMannheim

Mini resistance of copper wire scale for temperature variations on back of slide - conversion tables on back

PIC Standard Rule Slide Mannheim Royal Artillery

trig formulae on the back + “R.A.” for Royal Artillery

PIC VF 0123Military Mannheim

“VF” model prefix on back of stock = military - mini resistance of copper wire scale for temperature variations on back of slide - identical to standard Mannheim - conversion tables on back

PIC VP114/PC 1Pocket Differential Rietz

VP prefix = Vest Pocket - Rietz but patented (GB411090) differential Trig scales - cm scale on back

Tombeur
ModelTypeCommentsThumbnail
A2Advanced Juggler's - System TombeurSpecialist/advanced rule for throwing patterns & juggling mechanics. Serial no. 004 blind-stamped in back.
Radix 2/10Desktop Log - System LeibnizDecimal/10-bit binary (base/2/base 10) rule. Serial no. 019 blind-stamped in back
S3Pocket Simple Juggler's - System TombeurSimple rule for throwing patterns & juggling mechanics. Serial no. 011 blind-stamped in back.
Troeger (Hans)
ModelTypeCommentsThumbnail
(NoName)Desktop PricingUncannily similar (visual & construction) to much earlier Swiss-made Lightning Calculator (Blitzrechner) of Ernst Billeter - extra % scale for discount &/or profit margin mark-up calculations - son of K. Emil Tröger who took over the company his father founded
Troeger (Karl Emil)
ModelTypeCommentsThumbnail
Lung Volumes and BreathingDesktop Medical long-scale

Standard values of AG Pathophysiologie d. Atmung - “1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” - Karl Emil founded the company later taken over by son Hans - 8 mini specialist scales overlaid on D scale

Neues Deutschland (ND)Desktop Typography printing - System B. Burghardt

Unmarked but obviously Karl Emil made - Neues Deutschland = East German daily newspaper - Cicero is a typographic unit of measure similar to a pica but with 15th century origins

No. 1 (ver. 37/393/6004) Desktop Basic plus“1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” - Karl Emil founded the company later taken over by son Hans
No. 2 (Haefele)Basic

For G. Haefele spinning & weaving mill - Karl Emil founded the company later taken over by son Hans but NOW operating out of same Kirchenthumbach address (see instructions) - Haefele mill now private car museum (Patina)

No. 2 (ver. 37/393/6004)Basic

“1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” - Karl Emil founded the company later taken over by son Hans

Trow, Isaac
ModelTypeCommentsThumbnail
Routledge EngineerJoint 2-fold Old Arched-hinged Coggeshall

D Girt line = 1-40 + “improved version” with gauge points & tables of engineering information on front + four-entry (split over 2 legs) INCH to ¼ scale table on back

TU - Kiev
ModelTypeCommentsThumbnail
125-10m Pocket Rietz

Equivalent ​ROCT (GOST) Russian State Standard No. = TY 25.01.610-72

250-10mRietz

ROCT (GOST) Russian State Standard No. = 5161-72

250-14mLog-Log

ROCT (GOST) Russian State Standard No. = 5161-72

Unique
ModelTypeCommentsThumbnail
"Unique" Mannheim (type 2) - earlyOne of the earliest Unique’s - table of Trig values & formulaes on back
10 L/LLog-LogTable of decimal equivalents of fractions in well of stock & Trig tables on back
10 L/LLog-Log - earlyEarly model made by Technical Supply Co - Trig tables on back
10/20Ten-Twenty long-scale Double-length scales giving 20” precision - table of decimal equivalents of fractions in well of stock - various conversion tables on back
10GLegible MannheimSelf-defeating innovation: less “tick marks” + more labelling = legibility but also less accuracy. Table of trig conversion factors on back
5 L/LPocket Log-LogLog Log type unhyphenated + no CI scale - Trig tables on back
5 L/LPocket Log-Log - earlyEarly model made by Technical Supply Co - Trig tables on back
5/10Pocket Five-Ten long-scale Double-length scales giving 10” precision - table of Trig ratios on back
5GPocket Legible MannheimSelf-defeating innovation: less “tick marks” + more labelling = legibility but also less accuracy. Table of trig conversion factors on back
Area CalculatorPocket Area Calculator - imperial

For calculating areas of 2-dimensional figures or shapes in imperial square yards or square feet - bottom scales 2 parts of a single folded scale (folded @ 6 sq. feet)

BBrighton DarmstadtOnly Unique with edge scales - despite unusual order of scales probably least unique Unique - table of decimal equivalents of fractions in well of stock & Trig formulaes on back
CCommercial - businessUnconventional rule for merchants working pre-decimal & in imperial - conversion tables on back
Caterers and ConfectionersRetail Cost & Portion Control

Unusually the majority of the scales are calibrated for pre-decimal British £sd – a non-decimal currency that does not directly lend itself to a logarithmic scale.

CostingMonetary - business Copyrighted design for calculating (i) pre-decimal ​£-s-d & (ii) piece-rate pay - table of decimal equivalents of fractions in well of stock
CraftPocket Retail Surface Area Costing

Deceptively simple way of calculating in feet & inches non-decimal imperial areas (l x w) of 2 dimensional figures + total pre-decimal cost for a given price/square foot for example timber​

D1Pocket Dualistic High-Speed long-scale P & Q scales are double-length C/D scales folded at pi, D2 & C2 scales are double-length D/C scales at root 10 - table of Decimal Equivalent of Fractions in the well & tables of properties of materials on back
D3Dualistic High-Speed long-scaleP & Q scales are double-length C/D scales folded at pi, D2 & C2 scales are double-length D/C scales at root 10 - table of Decimal Equivalent of Fractions in the well & table of properties of Trig Ratios on back
Double HExperimentalOnly known duplex model by Unique - name possibly derived from the profile of aluminium end braces - nonstandard scale layouts - simplex cursors glued back-to-back​
EElectrical/Electro - earlyUnconventional layout (CF & DF & gauge points instead of W scale) - possibly made by Technical Supply Co. - Resistivity & Temperature Coefficient table on back
FFlorida Enhanced MannheimExtra narrow + imperial/metric conversion factors on back
F.S. Ratcliffe (Rachdale) Ltd Spring Calculating poly-slide (2)

For helical tension & compression spring calculations - upper slide for stress & load/lower slide for spring rate + two tables & graph on back

F5Pocket Florida Enhanced Mannheim without Trig scalesExtra narrow - table of decimal equivalents of fractions in well of stock + trig ratios on back
Friel-SturdyRadiographic Exposure CalculatorFor determining exposure times for medical X-rays - developed (prov. patent 29187/45) by two esteemed radiographers: Friel & Sturdy - table of conversion factors in well - table of bone densities (?) on back of slide - table of absorption values on back
General Post Office (GPO)Transmission Equivalent Resistance (TER) No. 1 for 50 V. BALLAST1/5 set for calculating the transmission-planning limit in telephone cable design - overall longer & wider than standard 10” models - table of supplemental factors on back
General Post Office (GPO)Transmission Equivalent Resistance (TER) No. 2 for 50 V. NON-BALLAST and SIEMENS No. 162/5 set for calculating the transmission-planning limit in telephone cable design - overall longer & wider than standard 10” models - table of supplemental factors on back
General Post Office (GPO)Transmission Equivalent Resistance (TER) No. 3 for 40 V. C.B.3/5 set for calculating the transmission-planning limit in telephone cable design - overall longer & wider than standard 10” models - table of supplemental factors on back
General Post Office (GPO)Transmission Equivalent Resistance (TER) No. 4 for 22 V. C.B4/5 set for calculating the transmission-planning limit in telephone cable design - overall longer & wider than standard 10” models - table of supplemental factors on back
General Post Office (GPO)Transmission Equivalent Resistance (TER) No. 5 for all exchanges5/5 set for calculating the transmission-planning limit in telephone cable design - overall longer & wider than standard 10” models - table of supplemental factors on back
George Mancell (London) LtdHarfield Weight Calculator for Steel

Extra narrow - calculates (imperial) total weight of steel bars (l x Lbs/ft) - tables of conversion factors & caculating aids on back

Harrison & Whitfield (Steel Stockbrokers)Harfield Weight Calculator for Steel

Extra narrow - calculates (imperial) total weight of steel bars (l x Lbs/ft) - tables of conversion factors & caculating aids on back

Interval CalculatorCalendar Days

# of days between 2 calendar dates - table of decimal equivalents of fractions in well - conversion tables on back for pre-decmal shillings & pence to £ + Cwts & quarters to tons

JiffyLilliput Enhanced Mannheim without Trig scalesUnmarked - “Jiffy” from cover of instructions & probably a refernce to: “done in a jiffy”
Loewy Engineering Co.Rolling Mill (steel) for Seperating Force and Torque poly-slide (2)Extra wide with nomogram in the centre - based on 1973 UK patent GB659754 (Antolij Mogiljanskij) - company give-away to buyers of Loewy equipment
MMonetary

Stripped back version (fewer scales) of the Commercial - monetary scales (M1, M2 & M3) 3 parts of single folded scale (1d-£5000) – folded at 10/- & £50 - Table of decimal equivalents of fractions in well of stock

Metal Box Co.Percentage Butting for metal seams

In metal can production the overlap is a key integrity factor of the finished product ​- % butting = amount of overlap in imperial inches needed for a sound seam - another version was made by BH

Mini-MannheimLilliput Enhanced Mannheim without Trig scalesParallel line logo
NNavigational

Has no specific marine-related scales but unconventionally having S & T on front of slide = possibly best rule ever for general calculations - air & wind speed conversions factors on back

OChemical Log-LogParallel line logo + overall longer & wider than standard Unique 10” model - tables of chemical atomic weights (A to Zr) in the well of the stock & a table atomic numbers for elements up to Nobelium on back
Pioneer Concrete (UK) LtdPocket Concrete Volume Computer

Calculates volume in cubic metres of concrete needed to fill conventionally shaped cavity (imperial or metric) - company name Pioneer Concrete (U.K.) Ltd. on back

Tube Investments LtdTubemaking and Deep DrawingExtra wide - various conversion tables & aids on back
U 10 L/LUniversal Log-LogOn all Log-Log models LU unconventionally = Log Upper (LL2) & LL = Log Lower (LL3) - incl. CI scale + tables of properties of materials on back
U1Universal I Log-LogUniversal I = Trig scales on stock - tables of conversion factor/densities of metals/densities of non-mtal materiels on back
U1Universal One Log-LogParallel line logo - tables of conversion factors on back
U1/2Pocket Universal I Log-LogTables of conversion factors/densities of metals/densities of non-mtal materiels on back
U2Universal II Log-LogUniversal II = Trig scales on slide - Trig formulaes on back
Wilkinson SugarMonetary - commodity price converter

Unusually a slide rule specifically designed for Anglo-American market & incorporating scales for 2 different pre-decimal currencies - table of decimal equivalents of fractions in well of stock

Unknown
ModelTypeCommentsThumbnail
"Consul" The Educated Monkey Replica Child's Teaching Aid/Calculator for simple arithmetic

Replica sold by ARITHMEUM - original Invented & patented (US1188490) by William Robertson in 1916 - “Consul” = name of famous performing monkey of the day - set x & ÷ problems with feet - results framed by monkey’s hands ​(+ & - problems need Addition Table card)​

(NoName)Desktop Gunter Rule

Invented by Edmund Gunter (1581-1626) - standard layout for a Gunter i.e. ​Diagonal scale on front face + full-length scales on back

(NoName)Desktop Poly-slide (2) Steel Bars & Sections Weight Calculator - imperial

Wide-bodied model possibly made by BH ​

(NoName)Desktop Steel Weight Calculator - imperial

Wide-bodied & well made but otherwise no clues as to the maker​ - scale layout identical to Robson model

(NoName)Gaugung Diagonal Line Rod

½ inch square rod with brass shaven tip used to measure diagonally the approximate content of casks (max 240 gallons) of similar aspect ratios

(NoName)Half Gunter Rule

​Diagonal scale on front face + full-length scales on back but no A scale

B.F. GrizzleWater Line Capacity

For calculating the friction loss in a section of pipe & head loss for a given pipe diameter, length & flow - layout based on Hazen–Williams equation - modern adaption of Lawrence-made model but with © renewed 1971

BalkenschuifWooden Floor & Ceiling BeamsConstructed (in conformance to Amsterdam building regulations) by K. Schippers whilst working as building superintendent for Rotterdam city council - probably made by in-house workshop
Carpenter Pocket Joint 4-fold Old Arched-hinged Coggeshall

D Girt line = 4-40 + 12-24 “Pence per Load” table & eight-entry ¼ to INCH½ scale table (split over 2 legs) on front

Carpenter TimberJoint 2-fold Large Plate-hinged Coggeshall

D Girt line = 4-40 + four-entry ¼ to INCH scale table on front + E & M scales (split over 2 legs) on back

Darnley's Rotable Lightning Calculator Children's Multiplication Table Teaching Aid/Pencil Case

Invented & patented (GB167699) as a teaching aid for 1 - 20 multiplication tables by Percy Darnley & Barnett Richards in 1920 - possibly inspired by earlier 1885 German patent (DE33155) of Peter Wiesenmüller - dark-blue & green versions also made + German 4-colour series branded ROKA

ElectrofloBoiler effeciency (150-250 lbs/inch) & energy costs© H.W. Healy 1923 - pinned construction suggests OEM rule by Unique or Hardtmuth
Flexider BeneluxPipe Expansion poly-slide (2)

Unusual patented design (? made by UK maker Blundell) with windows on both sides of stock revealing scales on 2 non-reversible slides + pictogram explaining formulas on back + Flexider Benelux b.v. was a NL company but is now part of Anamet Europe

HABSChildren's Multiplication Table Teaching Aid

German patented (D.R.P.) teaching aid for 1 - 20 multiplication tables - name HABS attributable to the German “Ich habe es” or “I have it” - Spanish “El Calculador” version also known to exist ​

MAGIC - BRAIN CALCULATORSlide Adder - silver/red

Made in Japan - single adder design for both addition & subtraction​ - many OEM versions sold

Noel-BentleyDesktop Paper Roll Computor poly-slide (2)

Robert Noel-Bentley design (patent CA489176 - 1952) for calculating (pre-shipment) physical characteristics of commercially manufactured large & heavy rolls of paper - possibly made by Blundell.

RG-44Demonstration Military Artillery Range Finding - System Grigorovich

Made for NVA 266 & 256 = German Nationale Volksarmee Infantry Division - instruction model for field version of RG-44 ​

Smarty CatChild's Teaching Aid/Calculator for Simple Arithmetic

Based on a 1953 Spanish patent (ES38332) by Cándido - snappy model name ​comes from cat face on both sides of cursor (line-up windows = eyes + mouth) + cat paw mark impressions on ends of stock (front & back) - 1 side for simple arithmetic + other side for multiplication - later version with multi-coloured bands on stock

TwaddellStrength of liquids

For measuring the acidity or sweetness of liquids - read more ...

Van Oosterhout, A
ModelTypeCommentsThumbnail
(NoName)Desktop Replica Gunter Rule

Invented by Edmund Gunter (1581-1626) - replica made by KRING member Ton van Oosterhout ​- standard layout for a Gunter i.e. ​Diagonal scale on front face + full-length scales on back

Napier BonesReplica Calculating Rods

Invented by Scot John Napier (1550-1617) replica set made by KRING member Ton van Oosterhoutset consisting of 1 multiplier rod + 10 multiplication table rods + 1 larger squares & cubes rod ​

VEB Fuellhalterfabrik MAKEBA
ModelTypeCommentsThumbnail
Makeba-KombinatorPencil MannheimMechanical drop-lead pencil incorporating a crude slide rule as part of the barrel
VEB MANTISSA
ModelTypeCommentsThumbnail
1802Climate & humidityMade for Feutron Klimasimulation GmbH for calculating with a max atmospheric pressure of 760 Torr
MultiPocket log-logCompany logo top right-hand corner
Venetsianos (Panagiotis)
ModelTypeCommentsThumbnail
Dr. Harologarithms of numbers Concept invented by Dr. Haro, a French army medical officer, & presented to a conference in 1887 but probably never went into production - CD version ingeniously made by Pano
W.H. Harling
ModelTypeCommentsThumbnail
702Desktop Enhanced Mannheim - early

No makers name or logo - catalogued by Colin Barnes as “Lloyds Register Slide Rule” - table of constants on back

Wed. J. Ahrend & Zoon
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791/7Diagonal Scale

Used with a set of dividers for scale ratios 1:1000, 1:5000,1:1250 & 1:2500​

Electro 15Electro

OEM version made by Koch, Huxhold & Hanneman but often mistaken as Dennert & Pape because of model no. - V & W scales in well of stock + conversion tables (in NL) on back

Hollandia-RekenstokEnhanced Mannheim

Hollandia-Rekenstok = Dutch calculating stick - OEM version made by Dennert & Pape - cm scale in well of stock + conversion tables (in NL) on back

West & Partners, A.
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GliderRietz

Possibly made by John Davis & Son - Glider name from slide-long slotted metal patented (GB232037 - L.E. Edwards) tensioning spring for “automatic” smooth sliding - steel back + paper table of conversion factors

White & Gillespie (W&G)
ModelTypeCommentsThumbnail
432Electro Dualface ComprehensiveHighly innovative thumb-wheel cursor for extra cursor positioning accuracy
476Dualface TrigonometricalVery unusual scale layout incl. Exsec-Versine & Arc-Chord
William Langley
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Carpenter TimberDesktop Coggeshall

Rare rectilinear Coggeshall with 4–40 GIRT LINE for volumes of round timber + 2 sets of brass gauge pins (marked 0,16, 8 & 8,16, 0 respectfully) for round, 8 or 16 sided timber + INVERTED LINE (AI scale) for volumes of rectangular timber - compared to Dring & Fage version layout front & back reversed

Wizard Werke GmbH
ModelTypeCommentsThumbnail
CALCULATING MACHINESlide Adder - silver/black

Single adder design both addition & subtraction ​

WK-Wohnen
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FarbschieberColour combinations for Interior Designers poly-slide (3)

Developed in cooperation with German Institute for Colour Psychology - all 3 slides & inside top/bottom edges of cursor “tongue and grooved” - all slides interchangeable & reversible - read more ...