Specially commissioned by German tool company Clarkson for drilling calculations + Tables of conversion factors on back 

Slide chart specially commissioned by German machine tool supplier W. Hegenscheidt (still operating) for drilling

Specially commissioned by German company Trilux offering international lighting solutions  + novel window in back for looking up lighting efficiency levels according to shape/configuration of lighting source 

Slide chart specially commissioned by defunct German producer of electrical equipment Allgemeine Elektricitäts-Gesellschaft AG (AEG) for looking up the properties of VPE cables of different kV, sizes, etc

Specially commissioned & copyrighted design by De Muiderkring the Dutch publishing arm of Amroh (American Radio House) specialising in radio technology + “half-duplex” layout with scales on back of closed frame stock + two cursor windows & tables in back - see much earlier 51903 version

Specially commissioned by  De Muiderkring the Dutch publishing arm of Amroh (American Radio House) specialising in radio technology + front & back scale layouts inexplicably reversed in respective Dutch instructions (De Muidenkring version considered correct)

Combined slide rule/slide chart specially commissioned by now defunct division of Dutch electronic multinational Philips for calculating required coil properties for ferroxcube cores   

Slide chart specially commissioned by international German producer of medical & safety technology products Drägerwerk AG & Co + tables of factors on back

Slide chart specially commissioned by German screw/springs/fastening producer Richard Bergner Holding GmbH  for calculating every possible aspect needed to choose the correct screw 

Specially commissioned by British producer GEC-Elliot Control Valves Ltd - copyrighted Fisher design + other versions made BH & Pickett 

Slide chart specially commissioned by defunct Dutch concrete pipe maker Eternit for calculating  friction factor according to Colebrook in water & sewerage pipes 

Slide chart specially commissioned by defunct German producer of INFA range of screws Jakob Faulstroh

Slide chart copyrighted design by LOROWERK specially commissioned by Dutch drainage experts Loromiej-Goor for choosing right diameter for drainage pipes/culverts

Slide chart specially commissioned by German international electrical engineering company JC Eckartdt according to a design by “Piston” (could also be type of valve) - cursor appears an over-kill 

Slide chart specially commissioned to a design by American building management company Honeywell for calculating expected noise emission of control & shut-off valves for a steam, gas or liquid flow + “e” suffix to model no. suggests other language versions made

Chunky slide chart according to a copyrighted design by F.W. Brüchen & specially commissioned by valve producer NELES that is now part of the Finish Valmet conglomerate - slide rule & documentation conforms to ISA-standards S 39.1 & 39.3

Slide chart specially commissioned by Swiss global energy management company Landis & Gyr for choosing most suitable servomotor 

Slide chart specially commissioned by defunct Dutch air conditioning company nedairco to help choose cooling load for room coolers + unusual vertical read out

Specially commissioned by German environmental simulation & air solutions company Vötsch Industrietechnik & rare reuse of unique IWAMATIC design for humidity calculations + conversion factors & nomogram on back 

Slide chart specially commissioned by German global air conditioning producer Gebrüder TROX to help choose correct baffles & silencers + versions in other languages (e.g. Dutch) exist

Slide chart (polish language) specially commissioned by global heating systems company Weishaupt for calculating heating requirements of buildings based on heating oil + sleeve & slide numbered for correct use

Copyrighted design specially commissioned by German company TB-SONDERBEDARF MESSTECHNIK for calculating relative humidity, etc

Combined slide rule/slide chart specially commissioned by now defunct German electrical retailer Robert Splettsen specifically for sizing American-made  Armstrong industrial humidifiers 

Slide chart copyrighted design specially commissioned by German company KRONE for calculating relative humidity, etc + impressive nomogram on back

Combined slide rule/slide chart specially commissioned by now German valve producer HERION-WERKE (now part of IMI Plc) specifically for sizing hydraulic & pneumatic valves

Slide chart specially commissioned by German producer DELBAG-LUFTFILTER (now part of global Hengst Filtration) for calculating the air take needed according to Colebrook equation   

Slide chart specially commissioned by Dutch metallurgy & metalworking company SMITFORT-STAAL for finding weight of sheet steel or bars with 1 of 3 profiles  

Slide chart for converting between various SI, legal, imperial & metric units

Generic but for French market

Slide chart specially commissioned by German international electrical engineering company JC Eckartdt - front pneumatic & back electrical but cursor appears an over-kill 

Slide chart for for converting SI, metric. UK & US units + results shown with decimal comma as prevalent in “metric countries” 

Slide chart for calculating advertising costs that doubles up as a showcase advertisement for IWA slide charts!  

Slide chart in style of a credit card for metric to metric or vice versa

Slide chart in style of a credit card for 2002 EU changeover to Euro - see later version with update exchange rates

Slide chart in style of a credit card for 2002 EU changeover to Euro - other language versions made  

Specially commissioned by Dutch quality control equipment supplier Haffmans for brewing & related industries + © design for calculating CO₂ % in beer by weight using formula devised by Dutchman J. van Strien when working for Dutch brewer Heineken + later sibling 14162 version for calculating CO₂ by volume

Specially commissioned by Dutch quality control equipment supplier Haffmans for brewing & related industries + © design for calculating CO₂ in beer by volume using formula devised by Dutchman J. van Strien when working for Dutch brewer Heineken + earlier sibling 14127 version for calculating CO₂ by weight

Slide chart specially commissioned by defunct German pharmaceutical company Kettelhack Riker for calculating the QRS complex part of cardiac cycles on an ECG graph - Tambocor Antiarrhythmikum is a branded medication for treating a life-threatening irregular or abnormal heartbeat    

Ruler to help cardiologists analyse printed electrocardiographs (ECG’s) traces from electrocardiogram machines for standard paper speeds of 25 or 50 mm/s

Slide chart specially commissioned French-German pharmaceutical company Ventis for calculating kidney creatinine clearance according to Cockcroft-Gault formula +  creatinine clearance nomogram on back   

Slide chart Flight Computer specifically for American Lockheed Corp. made F-104G Starfighter interceptor fighter-bomber widely deployed during Cold War

Combined slide rule/slide chart specially commissioned by German specialist ink maker Michael Huber München (now part of hubergroup) for calculating  aspects of typesetting & printing

Slide chart for calculating speed of a sailing yacht deepening on wind speed & apparent wind direction  

Specially commissioned (2500 made) & exclusively sold by German music retailer Verlag Erwin Bochinsky ​(trading name Verlag Das Musikinstrument) + based on earlier prototype by German master piano builder Klaus Fenner for wound & unwound strings + calibrated for imperial & metric sizes + table on back for recalibrating steel core wound strings

Slide chart in style of a credit card for mixing 22 different cocktails + with half no. of cocktails but uncannily similar to BH version

Slide chart specially commissioned by German broadcaster for south-west Südwestrundfunk (SWF bur these days SWR) for finding best FM radio reception for stations SWF1, SWF2 & SWF3 based on location of broadcasting antenna

Innovative patented (US3374947) design by Swede Carl Wern that uniquely eliminated age old decimal point problem + copyrighted table of worked examples on back of wallet 

IWAMATIC uses a unique planetary design mechanism with two connected inner discs invented by Winfried Lück whereby turning one disc turns the other at half speed  + costly design with conversion tables on back but quickly outdone by arrival of electronic pocket calculator - see specially commissioned VÖTSCH version 

Slide chart specially commissioned to a design by American building management company Honeywell  for calculating correct valve for a steam, gas or liquid flow  + table of Flow Coefficients on back of instruction card + 2nd 06 22 model no. on slide

Specially commissioned & copyrighted design by De Muiderkring the Dutch publishing arm of Amroh (American Radio House) specialising in radio technology + “half-duplex” layout with scales on back of closed frame stock + two cursor windows & tables in back - see modern  0257 version

Specially commissioned & copyrighted design by De Muiderkring the Dutch publishing arm of Amroh (American Radio House) specialising in radio technology + “half-duplex” layout with scales on back of closed frame stock + two cursor windows & tables in back - looks like reissued plastic version of 51903 

Specially commissioned by family run international producer of yam Reiners + Fürst   

Specially commissioned by German radio maker Ultrakust-Gerätebau & probably designed by Dr. O. Raudszus for calculating air pressure + impressive nomogram

 Slide chart with novel half-round design specially commissioned by German merchant for grinding materials Carborundum + table of grinding bases on back

Slide chart specially commissioned by German collective Vereinigte Drehbank-Fabriken (VDF) - copyrighted design