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

Search my slide rule collection

Search by maker

Search by keyword

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

Search papers

Interested in finding out more out about such calculating wonders? Then try one of the slide rule related articles (often light-hearted) I have published.
Go to the search papers page.

Search results: Click on any Model listed in the left-hand column for its full specification OR hover over its "Thumbnail" (if shown) for a pop-up enlargement of the image

You searched for: ALRO (All-Round)
ModelTypeMaterialCommentsThumbnail
10 R T.K.F. (AC-1.45b) Waistcoat Rietz plastic/metal

​Version made for T.K.F. = Twentsche Kabelfabriek (Twentsche Cable Factory) was originally a cable manufacturer based in Dutch town Haaksbergen but is now a leading supplier of connectivity solutions

ALRO 10 R T.K.F. (AC-1.45b) Waistcoat Rietz
100 R (AC-1.04a) Rietz metal/paper

With the primary scales nearest to the rim this scale layout offered great precision (scale length 28cm) over the more popular 200 R that had the Trig scales nearest to the rim

ALRO 100 R (AC-1.04a) Rietz
100 R (AC-1.04b) Rietz - early metal/paper

With the primary scales nearest to the rim this scale layout offered great precision (scale length 28cm) over the more popular 200 R that had the Trig scales nearest to the rim 

ALRO 100 R (AC-1.04b) Rietz - early
1010 Commercial (AC-1.17) Business long-scale metal/paper

Circular cursors only version of innovative but impractical single long-scale 6-spiral patented (CH265561) design + tables of conversion factors in lid - try out an online simulation created by Andries de Man

ALRO 1010 Commercial (AC-1.17) Business long-scale
1010 Commercial (AC-1.18) Business long-scale metal/paper

Circular and radial cursor version of Innovative but impractical single long-scale 6-spiral patented (CH265561) design  + tables of conversion factors in lid - try out an online simulation created by Andries de Man

ALRO 1010 Commercial (AC-1.18) Business long-scale
200 R (AC-1.05a) Rietz metal/paper

​Table of conversion factors in lid  + Dutch retailer Bladergroen was an stationer from 1903 to 1980 when it was bought out & name changed to Berlage  - try out an online simulation created by Andries de Man

ALRO 200 R (AC-1.05a) Rietz
200 R (AC-1.05a) Rietz - H - early metal/paper

Code H alongside central nameplate probably = country code for Holland + table of conversion factors in lid

ALRO 200 R (AC-1.05a) Rietz - H - early
200 R (AC-1.05a) Rietz - two-tone metal/paper

Reason for two-tone paper unknown - table of conversion factors in lid

ALRO 200 R (AC-1.05a) Rietz two-tone
200 R (AC-1.05b) Rietz - early metal/paper

Conversion chart (fractions/decimals) in lid

ALRO 200 R (AC-1.05b) Rietz - early
200 R (AC-1.05b) Rietz - green metal/paper

Reason for green/turquoise paper unknown & for polished inside box is unknown

ALRO 200 R (AC-1.05b) Rietz - green
200 R (AC-1.05b) Rietz - H metal/paper

​Code H alongside central nameplate probably = country code for Holland + ​conversion chart (fractions/decimals) in lid

ALRO 200 R (AC-1.05b) Rietz - H
200 R (AC-1.05b) Rietz - heavy metal/paper

Because of a shortage of aluminium during WWII the metal boxes looked the same but were, for a short time, made of much heavier zinc - code H alongside central nameplate probably = country code for Holland + ​conversion chart (fractions/decimals) in lid

ALRO 200 R (AC-1.05b) Rietz - heavy
200 RL (AC-1.49) Rietz - monochrome plastic

RL = Rietz Liniaal (ruler) + later (CI scale no longer red) improved version with self-lubricating bearings + 2 windows with hairline, two expansion slots & table of constants for metals on back

ALRO 200 RL (AC-1.49) Rietz - monochrome
200 RL (AC-1.49) Rietz plastic

RL = Rietz Liniaal (ruler) + failed project to make white plastic linear model + 2 windows with hairline, two expansion slots & table of constants for metals on back - part of prototype batch of +/- 50  

ALRO 200 RL Rietz
300 D (AC-1.08a) Darmstadt metal/paper

Early version without P scale  + table of conversion factors in lid - subsequently succeeded by 400 D

ALRO 300 D (AC-1.08a) Darmstadt
300 D (AC-1.08b) Darmstadt - early metal/paper

Later version with added P scale + missing paper scales in lid - subsequently succeeded by 400 D 

ALRO 300 D (AC-1.08b) Darmstadt - early
400 D (AC-1.09) Darmstadt metal/paper

Successor to 300 D with many more gauge marks & CI replacing S&T & P in lid + table of conversion factors in lid ​- see also larger sibling

ALRO 400 D (AC-1.09) Darmstadt
400 D (AC-1.nn) Desktop Darmstadt metal/paper/plastic

See also smaller sibling - conversion table of fractions also on back 

ALRO 400 D (AC-1.nn) Desktop Darmstadt
50 Ng (AC-1.47) Waistcoat Basic Printing/Conversion plastic/metal

Ng = Normaal (normal) grafici (printers) ​+ scales on back convert mm into cicero’s/didot points

ALRO 50 Ng (AC-1.47) Waistcoat Basic Printing/Conversion
50 Nmmi (AC-1.46a) Waistcoat Basic/Conversion plastic/metal

Nmmi = Normaal (normal) mm to inches + scales on back convert metric mm into imperial inches  

ALRO 50 Nmmi (AC-1.46a) Waistcoat Basic/Conversion
500 N (AC-1.11) Basic metal/paper

N = Normaal (normal) & is possibly successor to Ha.A2 but with smaller font to make more room for advertising + see also larger sibling - tables of conversion factors from 1010 Commercial in lid

ALRO 500 N (AC-1.11) Basic
500 N (AC-1.nn) Desktop Basic plastic/metal/paper

N = Normaal (normal) + personally enhanced (lighter plastic outer baseplate & peripheral cursor hairlines) model of last ALRO Technical Director Han Wanders - see also smaller sibling 

ALRO 500 N (AC-1.nn) Desktop Basic
500 N Vergouts (AC-1.11) Basic metal/paper

N = Normaal (normal) & is possibly successor to Ha.A2 but with smaller font to make more room for advertising such as Belgium photographers Vergouts + tables of conversion factors from 1010 Commercial in lid

ALRO 500 N Vergouts (AC-1.11) Basic
600 E (AC-1.19) Electro metal/paper

Rare example of circular Electro type ​

ALRO 600 E (AC-1.19) Electro
746 De Muiderkring (AC-1.27) Radio metal/paper

De Muiderkring = the Dutch publishing arm of Amroh (American Radio House) specialising in radio technology + pictogram colour coding & table of resistances for condensers in lid - see also waistcoat sibling

ALRO 746 De Muiderkring (AC-1.27) 746 Radio
746 De Muiderkring (AC-1.nn) Waistcoat Radio plastic/metal

De Muiderkring = the Dutch publishing arm of Amroh (American Radio House) - see also larger sibling 

ALRO 746 De Muiderkring (AC-1.nn) Waistcoat Radio
AMI-RO-METER Boehringer Ingelheim (AC-4.01) Medical plastic

Slide chart for calculating the probability of a myocardial infarction (heart attack) in patients with history of heart problems + Boehringer Ingelheim = Dutch research-driven global pharmaceutical company + AMI-RO = Acute Myocardial Infarction Rotterdam ​

ALRO AMI-RO-METER Boehringer Ingelheim (AC-4.01) Medical
BoB3 (AC-1.nn) Reinforced Concrete - System Dussel metal/paper

Personally designed by company co-founder C.J. Dussel + BoB3 = possibly Beton (concrete) & part of alternative model numbering system + possible forerunner to later (?) Beton version but with additional 70 kg/cm2 scale & extensions for extra strong cement + scales in  lid are for calculating no. & size of reinforcement bars

ALRO BoB3 (AC-1.nn) Reinforced Concrete - System Dussel
Chem (AC-1.23) Chemical metal/paper

Chemical credence comes from over 140 chemical-related gauge marks + table of all atomic weights from 1948 in lid - see also online simulation by Andries de Man 

ALRO Chem (AC-1.23) Chemical
DAST (AC-6.01) Lilliput Calendar plastic

Slide chart DAST = DAtum (date) STandaard (standard) is a perpetual calendar for the years 1300 to 2499

ALRO DAST (AC-6.01) Lilliput Calendar
DECIBEL PHILIPS TELECOMMUNICATION (AC-1.44) Waistcoat Radio plastic/metal

Larger versions made for PTT 

ALRO DECIBEL PHILIPS TELECOMMUNICATION (AC-1.44) Waistcoat Radio
DECIBEL PTT (AC-1.42) Radio plastic/metal

PTT = Posterijen, Telegrafie en Telefonie or old Dutch post, telegraph & phone company & ​NL NR 04 - 2220 = ordering no. + see smaller sibling

ALRO DECIBEL PTT (AC-1.42) Radio
DECIBEL PTT (AC-1.44) Pocket Radio plastic/metal

PTT = Posterijen, Telegrafie en Telefonie or old Dutch post, telegraph & phone company & ​NL NR 04 = ordering no. + see larger sibling

ALRO DECIBEL PTT (AC-1.44) Pocket Radio
Delta Lloyd (AC-2.25) Pocket Building wood/celluloid veneers

Slide chart/ruler made for Dutch insurance company Delta Lloyd with unusual mirrored (anamorphosis) scale to measure thickness of framed glass by placing the bevelled top edge against the glass surface & reading off the thickness from the reflection in the glass

ALRO Delta Lloyd (AC-2.25) Pocket Building
DISCABOIS (AC-1.24) Forestry - System Brouhon metal/paper

Patented design (BE492292) by J.L. Brouhon from 1949 for wood merchants, wood sawmills, etc + tables of conversion factors from 1010 Commercial in lid + price included surcharge over other Ø 13cm models - see also online simulation by Andries de Man 

ALRO DISCABOIS (AC-1.24) Forestry - System Brouhon
EMF DORDT (AC-3.10) Electro plastic

Slide chart for calculating power, efficiency & wiring of electric motors + EMF DORDT = nickname of defunct Dutch company Willem Smit & Co.‘s Electromotorenfabriek that produced large commercial electrical motors

ALRO EMF DORDT (AC-3.10) Electro
GRASSO-PERSLUCHT (AC-2.22) Refrigerant/Conversion plastic

For air pressure & flow calculations + GRASSO-PERSLUCHT = Dutch company for industrial refrigeration equipment + table of constants/conversion factors & ALROPRINT on back 

ALRO GRASSO-PERSLUCHT (AC-2.22) Refrigerant/Conversion
gti installatietechniek (AC-2.10) Central Heating plastic

Slide chart for converting heat transfer values in central heating systems + gti installatietechniek = Dutch plumbing company + ALROPRINT & © TRD/1977/10

ALRO gti installatietechniek (AC-2.10) Central Heating
Ha Tex (AC-1.16b) Business/Textile metal/paper

Ha Tex = Handel (business) Textiel (textiles) for textile based calculations with UK pre-decimal £sd currency & yards + tables of conversion factors from 1010 Commercial in lid - see also online simulation by Andries de Man

ALRO Ha Tex (AC-1.16b) Business/Textile
Ha.A2 (AC-1.12) Basic Retail metal/paper

Ha.A2 possibly part of alternative model numbering system & predecessor to 500 N AC-1.11 but with larger font & 4 pre-decimal & imperial conversion scales in lid + prefix Ha = possibly Handel (retail)

ALRO Ha.A2 (AC-1.12) Basic Retail
HYDRAULIC RELATIONS IN DRILLING B.I.P.M. (AC-2.01) Petroleum plastic

​Slide chart for calculating optimum drilling of wells according to factors such as pentration rate, drill speed, pressure drop, etc + B.I.P.M. = Bataafse Internationale Petroleum Maatschappij or forerunner of company now known as Shell

ALRO HYDRAULIC RELATIONS IN DRILLING B.I.P.M. (AC-2.01) Petroleum
Klinische Rekencirkel (AC-1.39) Desktop Medical System Lips metal/paper

Highly complex specialised layout of scales designed by Dr. A. Lips + facilitates 26 medical based calculations (metabolic-related on front & blood ph/gasses on  back) - read more … or try out  Andries de Man's two online simulations: (i) front & (ii) back 

ALRO Klinische Rekencirkel (AC-1.39) Desktop Medical System Lips
KLM CONVAIR 240 (AC-1.nn) Aviation metal/paper

Load adjuster (possibly pre-production) made for Dutch airline KLM who had 1st fleet in Europe of American-made Convair 240 passenger planes - see also earlier prototype sibling  

ALRO KLM CONVAIR 240 (AC-1.nn) Aviation
KLM CONVAIR 240 (AC-1.nn) Aviation - prototype metal/paper

Load adjuster prototype made for Dutch airline KLM who had 1st fleet in Europe of American-made Convair 240 passenger planes + table of conversion factors in lid - see also later (possibly pre-production) sibling

ALRO KLM CONVAIR 240 (AC-1.nn) Aviation - prototype
KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion metal/plastic/paper

Slide chart made for Dutch airline KLM (old style logo) for converting imperial & US gallons to lbs, kg, etc for range & loading calculations - see also all-metal early version & prototype

ALRO KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion
KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion - early metal/paper

All-metal silver coloured slide chart made for Dutch airline KLM (old style logo) converting imperial & US gallons to lbs, kg, etc for range & loading calculations - see final production model

ALRO KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion - early
KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion - prototype metal/paper

Prototype slide chart made for Dutch airline KLM (old style logo) converting imperial & US gallons to lbs, kg, etc for range & loading calculations + strange reference to Portugal's Lisbon Portela airport- see final production model

ALRO KLM Petrol & Oil Tables (AC-1.29) Petroleum/Conversion - prototype
KLM SYST ALRO - System van Roon (AC-1.35) Desktop Navigational metal/paper

Desktop version of smaller GoA with high-precision goniometric layout (double length Trig scales) by van Roon + specially commissioned flight computer for Dutch airline KLM for calculating course & wind correction 

ALRO KLM SYST ALRO - System van Roon (AC-1.35) Desktop aviation
KLOOS (AC-1.30) Steel Constructions plastic/paper

Slide chart for calculating steel forms needed to construct: (i) fixed & opening bridges & (ii) points & crossing for railways & tramways + KLOOS = F. Kloos en Zonen’s originally a Dutch ship builder that evolved into making all manner of heavy-duty steel constructions

ALRO KLOOS (AC-1.30) Steel Constructions
KNM BEGEMANN (AC-2.27) Pipe Flow plastic

Slide chart for calculating resistance in pipes (front) & pump capacity needed (back) + KNM Begemann = defunct Dutch company Koninklijke Nederlandsche Machinefabriek v/h E.H. Begemann manufacturing pumps & steel constructions + table of resistance values on back ​

ALRO KNM BEGEMANN (AC-2.27) Pipe Flow
Lici Transistor CdS (AC-1.41) Pocket Photographic plastic

Unusual battery-driven light exposure meter (with built-in micro measuring cell) made for Phlip van Meeuwen (GFK) 

ALRO Lici Transistor CdS (AC-1.41) Pocket Photographic
MILITAIRE REKENSCHIJF (AC-1.32) Military Terrain Analysis metal/paper

Made for Dutch Army with scales calibrated in NATO Milliradian (Mils) ​for angular measurement + pouch with belt clip shows it was intended for use in field of action 

ALRO MILITAIRE REKENSCHIJF (AC-1.32) Military Terrain Analysis
MILITAIRE REKENSCHIJF (AC-1.33) Military Terrain Analysis - monochrome metal/paper

Made for Dutch Army with scales calibrated in NATO Milliradian (Mils) ​for angular measurement but being metal cased version was for army barracks or classroom/study 

ALRO MILITAIRE REKENSCHIJF (AC-1.33) Military Terrain Analysis - monchrome
MILITARY CALCULATOR (AC-1.nn) Military Terrain Analysis metal/paper

Made foreign armies with scales calibrated in NATO Milliradian (Mils) ​for angular measurement but being metal cased version was for army barracks or classroom/study 

ALRO MILITARY CALCULATOR (AC-1.nn) Military Terrain Analysis
MOEDERS VOOR MOEDERS (AC-4.11) Medical plastic

Slide chart for pregnant mother’s in the early stages of pregnancy so they can plan when to donate urine to help other couples with fertility problems + Moeders voor Moeders = Dutch pharmaceutical company that extracts hCG hormone from the urine to create fertility medicines

ALRO MOEDERS VOOR MOEDERS (AC-4.11) Medical
MUD WEIGHT - FLOWING WELL B.I.P.M. (AC-2.02) Petroleum plastic

Slide chart for calculating needed & allowable maximum mud weight for a drilled & flowing well according to factors such as depth, pressure within drill pipe, annular surface pressure, etc + B.I.P.M. = Bataafse Internationale Petroleum Maatschappij or forerunner of company now known as Shell

ALRO MUD WEIGHT - FLOWING WELL B.I.P.M. (AC-2.02) Petroleum
Ned. Octr. Aangevr. (AC-1.03) Rietz metal/paper

Ned. Octr. Aangevr. = Dutch patent applied for so possibly an early pre-production model with CJD monogram for company co-founder Dussel + imperial conversion factors in lid - sadly metal box & patent nameplate are replacements   

ALRO Ned. Octr. Aangevr. (AC-1.03) Rietz
NIPO INDICATOR (AC-7.09) Statistics plastic

​Slide chart for calculating the significance between two independent statistical samples + NIPO = Nederlands Instituut voor Publieke Opinie (Dutch institute for public opinion) + table of conversion factors for reliability on inner slide

ALRO NIPO INDICATOR (AC-7.09) Statistics
Oil Spill (AC-7.06) Petroleum plastic

​Slide chart with © design Dept. of Transport & Public Works of The Netherlands for predicting the probable outcome of an oil spill based on spread, drift, mass balance, evaporation, dispersion & emulsification

ALRO Oil Spill (AC-7.06) Petroleum
PHILIPS AUDIO COMMUNICATIIONS (AC-3.02) Electro/Conversion plastic

​Slide chart for calculating dB decibel ratios & converting them into various current, voltage & power ratios

ALRO PHILIPS AUDIO COMMUNICATIIONS (AC-3.02) Electro/Conversion
PLANISFEER (AC-6.05) Desktop Astronomy plastic/cardboard

Slide chart designed as planisphere by Dutchman R. Walrecht to calculate star positions & star signs in Northern Hemisphere (52º North Lat. & 5º East Long.) for given date & time + just 1000 made

ALRO PLANISFEER (AC-6.05) Desktop Astronomy
RADIOLOGISCHE REKENSCHIJF (AC-7.01) Pocket Military Radiation plastic

For Dutch military personnel (NATO NSN no. 6665-17-055-1115) to calculate the effects & fall out directly after a nuclear explosion

ALRO RADIOLOGISCHE REKENSCHIJF (AC-7.01) Pocket Military Radiation
Radiologsche rekenschijf PTT (AC-7.02a) Radiation plastic

Part slide chart for calculating radioactive doses & intensities from a 1978 patented design (US4117315) from C.G.F. Amy & K.K. Keimpema+ issued as 4/8/1075/76346 by PTT = Posterijen, Telegrafie en Telefonie or old Dutch post, telegraph & phone company

ALRO Radiologsche rekenschijf PTT (AC-7.02a) Radiation
rekenschijf geluidsniveauverschil van gevels (AC-7.03) Building Facades plastic

Slide chart for calculating sound levels in dB for building facades - © 1983 design by ministerie  V en M = now defunct Dutch Ministerie van Volksgezondheid en Milieuhygiëne (Ministry of Health and Environmental Hygiene)

ALRO rekenschijf geluidsniveauverschil van gevels (AC-7.03) Building Facades
rekenschuif spoorweglawaai (AC-7.04) Transport plastic

For predicting railway trackside noise level in dB(A) according to several parameters e.g. noise screen, type & frequency of trains, average speed, etc - ALROPRINT 922130

ALRO rekenschuif spoorweglawaai (AC-7.04) Transport
SHELL VISCOKLOK (AC-1.40) Petroleum plastic/metal

Shell © clock (klok) design for calculating in 4 standard units viscosity of various oils at different temperatures - try out an online simulation created by Andries de Man

ALRO SHELL VISCOKLOK (AC-1.40) Petroleum
SIRKORSKY S-51 (AC-1.nn) Aviation - prototype metal/paper

Rare load adjuster for an American helicopter + prototype possibly made for aviation branch of Dutch Navy (Marine Luchtvaartdienst - MLD) who nicknamed it Jezebel 

ALRO SIRKORSKY S-51 (AC-1.nn) Aviation - prototype
ST 9-430/2 (AC-1.34a) Military Artillery Range Finding (1 of 2) plastic/paper

One of a pair of rules, without slides but with erasable cursors faces for hand-drawn pencil hairlines, made for the Dutch Army – the laminated (Alroderen™) paper tables & model # are ex-Army

ALRO ST 9-430/2 (AC-1.34a) Military Artillery Range Finding (1 of 2)
ST 9-430/2 (AC-1.34b) Military Artillery Range Finding (2 of 2) plastic/paper

Two of a pair of rules, without slides but with erasable cursors faces for hand-drawn pencil hairlines, made for the Dutch Army – the laminated (Alroderen™) paper tables & model # are ex-Army

ALRO ST 9-430/2 (AC-1.34b) Military Artillery Range Finding (2 of 2)
SYNRES (AC-2.23) Paint Conversion plastic

​Slide chart converting viscosity values between various standardised units + SYRES = Dutch company (still operating) specialising in commercial coatings & resins for buildings, boats, cars, etc 

ALRO SYNRES (AC-2.23) Paint Conversion
Time Zones NEC (AC-6.04) Conversion plastic

Slide chart made for Nederlandse Export Combinatie (NEC) for converting time across 7 times zones in 28 cities around the world 

ALRO Time Zones NEC (AC-6.04) Conversion
Truck Tyre Performance (AC-1.20) Commercial Transport metal/paper

 CJD monogram of company co-founder Dussel suggest an early model + 3rd party Table of Truck Tyre Pressures in lid

ALRO Truck Tyre Performance (AC-1.20) Commercial Transport
Verkeerslawaai (AC-7.05) Transport - green & black plastic

For predicting traffic sound levels according to several parameters such as type of road, type of vehicle, etc according to design by H.J. van Zuylen + Nationale Verkersakademie Tilburg = defunct Dutch technical school in Tilburg for educating traffic specialists

ALRO Verkeerslawaai (AC-7.05) Transport
WeM (AC-1.nn) Rietz metal/paper

WeM is part of alternative model numbering system + WeM = possibly Werktuig- en Machinebouw (mechanical engineering/machine industry) + possible forerunner to later (?) 200 R

ALRO WeM (AC-1.nn) Rietz
WeR2 5 (AC-1.07b) Rietz metal/paper

WeR2 is part of alternative model numbering system + WeR = possibly WeRktuigbouw (mechanical engineering) + suffix 5 possibly = version no. + possible forerunner to later (?) 100 R

ALRO WeR2 5 (AC-1.07b) Rietz