• 455 Martinson, Los Angeles
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  • Koch, Huxhold & Hannemann (KHH) - made surprising System Korte slide rule that does addition & subtraction
  • Smallwood Folding Shoe Sizing Stick in metric for French shoe sizes 10-48 in increments of a Paris point (⅔ cm)
  • Lawrence MIT Antenna slide rule for radar antenna performance was classified during WWII by UK & US governments
  • ALRO-made ruler unusually with a cursor for analysing ECG printouts of the cardiac Sinus Rhythms
  • Hatters Gauge - for measuring the size of a hat but unusually calibrated in metric & imperial
  • Glovers Rule - for measuring the length of a glove in imperial inches
  • Unusual non-logarithmic QR 41 military model by Dennert & Pape (D&P) for training anti-aircraft gunners
  • Colour combinations slide rule made by German WH-Wohnen for Interior Designers
  • Professor Fuller’s Drum Calculator from 1878 - made by W.F. Stanley
  • Modern wristwatch with slide rule bezel calculator made by German maker Kienzle
  • Ruxton made Multi-Vider combined drop-lead pencil & slide rule
  • Rare Otis King Model N for Retail & Monetary with white scales (422 & 424) on a black background
  • Darnley’s Rotable Lightning Calculator/Pencil Case calculating aid
  • Makeba made Kombinator combination pencil & slide rule
  • Rare Carbic-made Fischer Calculator slide rule
  • Specialist slide rule for a national home cable radio broadcasting system offered in The Netherlands from 1930 to1970
  • Smallest drum (≈ 2.4m) made by renowned Swiss maker LOGA

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You searched for: AHREND (Wed. J. Ahrend & Zoon)
ModelTypeMaterialCommentsThumbnail
(P281) Demonstration Rietz wood/celluloid veneer

made by unknown 3rd party for Hemmi models P280/P281 - Rietz layout but all scales on front face

AHREND (Wed. J. Ahrend & Zoon) (P281) Demonstration Rietz
435064 (89) Pocket Rietz plastic

OEM by ARISTO + reversed inch scale, cursor window with 1 hairline, Ahrend branding & closed Dutch industrial motor manufacturer De Industrie in back

435660 (P280) Darmstadt-like two-tone plastic

OEM by HEMMI

AHREND (Wed. J. Ahrend & Zoon) 435660 (P280) Darmstadt-like
435661 (P281) Rietz-like two-tone plastic

OEM by HEMMI

AHREND (Wed. J. Ahrend & Zoon) 435661 (P281) Rietz
435662 (P283) Technical two-tone plastic

OEM by HEMMI

AHREND (Wed. J. Ahrend & Zoon) 435662 (P283) Technical
642T Rietz bamboo/plastic/celluloid veneers

OEM by HEMMI as wider version of 64T Extended Rietz + T model no. suffix possibly = basic 64 with extra Trig scales + table of constants & green pads on back + earlier thinner 64T sibling - also sold as Ahrend 643T

AHREND (Wed. J. Ahrend & Zoon) 642T Rietz
74 Pocket Rietz - late bamboo/celluloid veneers

OEM by HEMMI with improved layout because of extra peripheral hairlines on cursor + metal backing plate + Dutch retailer Ahrend printed on back

791/7 Diagonal Scale nickel silver

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

AHREND (Wed. J. Ahrend & Zoon) 791/7 Diagonal Scale
810 Diagonal Scale nickel silver

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

ELECTRO 15 Electro wood/celluloid veneers

OEM version made by KHH (5 slits in well + 5 adjustment screws on bottom side edge) but often mistaken as D&P because of model no. - V & W scales in well of stock + conversion tables (in NL) & 2 cursor windows in back - see also identical model sold by, Johann Faber, OHICO & Kahn Frères

AHREND (Wed. J. Ahrend & Zoon) ELECTRO 15 Electro
ELECTRO 654 Electro wood/celluloid veneers

OEM by KHH (5 slits in well + 5 adjustment screws on bottom side edge) & identical to Electro 15 model but possibly renumbered to avoid confusion with D&P model no. - V & W scales in well of stock + conversion tables (in NL) & 2 cursor windows in back

AHREND (Wed. J. Ahrend & Zoon) ELECTRO 654 Electro
HOLLANDIA-REKENSTOK Enhanced Mannheim wood/celluoid veneers

Hollandia-Rekenstok = Dutch calculating stick - OEM version by Dennert & Pape & 1st slide rule in Ahrend catalogue - cm scale in well of stock + conversion tables (in NL) on back

AHREND (Wed. J. Ahrend & Zoon) HOLLANDIA-REKENSTOK Enhanced Mannheim
NORMAL 650 (Ver. 1) Enhanced Mannheim wood/celluloid veneers

OEM by KHH (5 slits in well + 5 adjustment screws on bottom side edge) + conversion tables (in NL) & 2 cursor windows in back

NORMAL 650 (Ver. 2) Enhanced Mannheim wood/celluloid veneers

OEM by KHH (1 slit in well + 5 adjustment screws on bottom side edge) + conversion tables (in NL) & 2 cursor windows in back

RIETZ 652 Rietz wood/celluloid veneers

OEM by KHH (1 slit in well + 5 adjustment screws on bottom side edge) + conversion tables (in NL) & 2 cursor windows in back

AHREND (Wed. J. Ahrend & Zoon) RIETZ 652 Rietz
RIETZ 690 (89) Pocket Rietz plastic

OEM by ARISTO + reversed inch scale, cursor window with 1 hairline & Ahrend branding in back