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Details of: AHREND (Wed. J. Ahrend & Zoon) - 810

Type? Generic name (e.g. Enhanced Mannheim) or function/use for special models (e.g. Meteorology). If not the “standard” 25cm linear length proceeded by the form (e.g. Demonstration, Desktop, Pocket, Waistcoat or Lilliput). Sometimes a suffix added to distinguish between different versions (e.g. early or late). Diagonal Scale
Sort? L/C/D/T/W/X where L=Linear, C=circular, D=Drum, T=tubular, W=watch, X=miscellaneous (i.e. the rest) L
Construction? Basic construction form of the body i.e. Closed/solid frame or Open frame or Duplex or Other Duplex
Material? Basic description: ivory/bone/wood/bakelite/plastic/metal/cardboard or combinations e.g. wood/veneered, wood/painted, etc nickel silver
Length? Mostly length in cm or ” (inches) of the D scale but excluding any scale extensions. But for circular or watch slide rules it is the diameter & for tubular or drum slide rules it is the overall linear scale length. For other mechanical aids it is the physical length. 30cm
Scales front? Standard (not maker’s) symbols for scales on front face e.g. A = X² (1-100) but § = generic symbol for any non-standard scale + scales between solidi / / are on the slide(s) whereas scales after vertical line | or after reversed solidus \ are on a straight or bevelled top or bottom side edge §,§
Scales back? Standard (not maker’s) symbols for scales on back face e.g. S = sine (5° to 90° & 85° to 0°) or sin(x) but § = generic symbol for any non-standard scale + scales between solid / / are on the back of slide(s) but scales listed after / / - notation are on another surface e.g. back of stock or inside a lid §,§
Cursor type? Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus none - not needed
Condition? Cn where n = 0-6 based on Herman van Herwijnen’s condition/quality scale
Date? YYYY for year(s) of production or an approximation/range of years 1950s
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc black linen covered (purple velevt lined) instrument case
Instructions? Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed
Comments ? Any special or noteworthy traits + significant use-related facts + pertinent details of scales/tables in well of stock + any significant tables, etc on the back of the stock

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

In-Out? MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known

All of:  AHREND (Wed. J. Ahrend & Zoon) new search?

ModelType
(P281) Demonstration Rietz
435660 (P280) Darmstadt-like
435661 (P281) Rietz
435662 (P283) Technical
791/7 Diagonal Scale
810 Diagonal Scale
ELECTRO 15 Electro
ELECTRO 654 Electro
HOLLANDIA-REKENSTOK Enhanced Mannheim
NORMAL 650 (Ver. 1) Enhanced Mannheim
NORMAL 650 (Ver. 2) Enhanced Mannheim
RIETZ 652 Rietz