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John Davis & Son (Derby) Ltd: Glider

John Davis & Son (Derby) Ltd Glider Rietz

Details of: John Davis & Son (Derby) Ltd - Glider

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). Rietz
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. 10"
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 \ K,A / B,C / D,L | 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,T /
Cursor type? Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus chrome/glass - 1 hairline + 1 window in back
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 1925
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc maroon hard case (compnay name stamped in gold lettering) + maroon-capped pop-stud
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

Glider name comes from slide-long slotted metal patented (GB232037 - L.E. Edwards) tensioning spring for “automatic” smooth sliding - steel back + paper table of conversion factors

In-Out? MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known <2010/

All of:  John Davis & Son (Derby) Ltd new search?

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