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Details of: AHREND (Wed. J. Ahrend & Zoon) - NORMAL 650 (Ver. 1)

Type? A generic name (e.g. Rietz) or function/use for specialist models (e.g. Meteorology) for grouping similar models across makers. If not “standard” 25cm linear length, preceded by the form (i.e. Demonstration, Desktop, Pocket, Waistcoat, Keyring, Lilliput or Book) + if needed, qualification to distinguish between versions (e.g. early or late). Enhanced Mannheim
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 Closed/solid frame
Material? Basic description: ivory/bone/wood/bakelite/plastic/metal/cardboard or combinations e.g. wood/veneered, wood/painted, etc wood/celluloid veneers
Length? Mostly the linear length of the D scale (in cm or inches) excluding any extensions. For circular/watch slide rules it is the diameter but for helical/tubular/drum slide rules it is the overall scale length. For other calculating aids it is the physical length. 25cm
Scales front? Standard (not maker’s) symbols for scales on front face e.g. A = X² (1-100) but § = generic symbol (signum sectiōnis) 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 cm \ A / B,C / D | inch
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 (signum sectiōnis) for any non-standard scale + scales between solidi / / 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 / S,L,T /
Cursor type? Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus metal/glass - 3 hairlines
Condition? Cn where n = 0-6  condition/quality scale where 0 = brand new in box & 6 = broken   C3
Date? YYYY for year(s) of production or an approximation/range of years
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc black linen covered stiff carboard case with A.W. Faber box mark
Instructions? Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed 1930s
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

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

In-Out? MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known 08-2020/

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

ModelType
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74 Pocket Rietz - late
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