A.W. FABER-CASTELL SLIDE RULE FEATURES -1920 Approximate Change Point STOCK & SLIDE -3-3 -3-5 -7-8 -20 Length 15 cm 12.5 cm scale 26 cm 350, 360, 365 26.4 cm 28 cm 354, 357, 363, 364, 367, 1. not 12.5 or 50 cm scale or, 378 28.5 cm 29.5 cm 378 Stock construction (a) 53.5 cm Single piece, solid 50 cm scale Single piece with 2 longitudinal slits in well not 369 Two piece, celluloid sprung Two piece, steel sprung Back of stock Flat back (no rebate and tables) non- 361, 366, 369*, 374, 377, 379, 384 Bottom edge of stock Rebated with paper tables Bevelled not 361, 366, 369*, 374, 377, 379, 384 361, 366, Cursor grooves (b) Perpendicular Split both edge rulers not 361, 366, Above top edge ruler but split bottom edge ruler Above both top & bottom edge rulers not Angled into stock at front/top edge join Slide Thumb Notch Slide runner Angled into stock at front/bottom edge join Right end of front At bottom of slide edge 361 Slots in back of stock to index back of slide Celluloid facings In centre of slide edge Right end (sin & log scales) Left end (tan scales) Front, well & front & back of slide not 361 not 361, 366 not 350, 360, 365 not 361, 366 Boxwood springs to tension slide Slide index end (c) Wooden fixing pins for celluloid Metal inserts Top & bottom edges Upper stock rail, below slide groove Upper stock rail, in slide groove Chisel index for well scales Stock Slide Longitudinal in stock & slide 354, 357, 363, 364, 365, 367 or 361 2. 3. 365, 378, 378, 379 or 12.5 cm scale SCALES -3-3 -3-5 -7-8 -20 Scale length 15 cm 369 369, 379
SCALES -3-3 -3-5 -7-8 -20 Scale length 15 cm 369 369, 379 25 cm not 369, 379, 380, 384 25.2 cm (approx.) Format of Mannheim scales (aa) 50 cm Plain (no railway tracks) Unequal double railway track 380 380, 384 option on 360, 363, 364, 365, 367 Double railway track & 50 cm scale 4. Marking method (d) Single railway track Hand printed scales or 50 cm scales 5. Template printed scales Lightly incised scales Rulers on edges Deeply incised scales Top edge, not to ends of stock not 6. 7. Bottom edge not to ends of stock 361, 366 Centimetre extension scale Inch/centimetre conversion scale (bb) Ticks on Mannheim scales (e) SLT scales M gauge mark (cc) Bottom edge to ends of stock On back of slide In well On back of stock On back of stock aligned to right slot index On A & B only On A, B, C & D On back of slide Script M (with long tail) on B only not 361, 366, not 50 cm scale or 361, 366,, 374, 377, 378 8. 380 8. not 361 367 9. Script M (with long tail) on A & B Serif M on A & B 10. or 12.5 or 50 cm scale or 366 11. 12. c & c1 gauge marks Electro scales Electro gauge marks Sans-serif M on A & B On D as well as C "Dynamo"/"Motor" & "Volt" scales in well Metric (287 & 736 on A & B scales) 14. not 12.5cm scale or 366, 378, 379, 378, 379 13. Imperial (287 & 746 on A & B scales), 378, 379 Log-log index marks Unlabelled on non-electro rules 2.9 on left & right ends of D 15. System Pickworth System Schumacher W on right end of C Cube scale and window on back of stock Non-logarithmic scales and indexes, 378, 379 374, 377 366 TEXT & LABELS -3-3 -3-5 -7-8 -20 Brand name Brand typeface 'A.W. Faber' 'A.W. Faber "Castell"' Gold serif non- non- & 50 cm scale non-
TEXT & LABELS Brand name Brand typeface Numbers on scale subdivisions (f) Scale numbering typeface (aa) Scale numbering marking (g) Origin ('MADE IN ') Quotient/Product ± on lower stock ends Arrow ± symbols (aa) Model number 'DRGM 98350' (1898) 'DRGM 116832' () 'DRGM 427514' () 'DRGM 271169' () 'DRGM 371190' () 'DRP 206428' () 'DRGM 344576' () 'DRGM 371189' () 'DRP 215722' () Back label style (bb) Back advertising label (bb) Paper Back label text style (dd) 'A.W. Faber' 'A.W. Faber "Castell"' Gold serif Gold sans-serif Black sans-serif Decimal notation Displaced 1.5/15 on A & B scales Style A Style B Style C Hand printed Template printed language rules Non-/non- language rules 'QUOTIENT +1' & 'PRODUCT -1' 'Quot.+1' & 'Prod.-1' On left & right upper stock ends 3-digit, followed by '*' before brand Boxwood springs in well for slide Slide end index edge for well scales Cursor with hook index for edge scales Wood fixing pins for celluloid Longitudinal metal inserts System Schumacher System Pickworth System Pickworth Style 1 () Style 2 () Style 3 () Style 4 () Style 5 () non- non- & 50 cm scale non- & 50 cm scale or 50 cm scale 350, 355, 360, 361, 363, 365 350, 355, 361, 363 17. 18. 363, 367 19. 354, 357 20., not, 369, 378, 379, not, 369, 378, 379 Style 6 (French) French, not, 369, 378, 379 Style 7 ( electro), 8 (Non- electro) Celluloid Style A Style B -3 Non- -3-3 50 cm scale & 363, 364, 367,, 374, 377 21. 22. 23. 24. 25. 363, 367 26. 27. 28. 363 29. ` -5, 378, 379, 378-7 -8 or 12.5 cm scale 366 374, 377 374, 377 369 369-20 369 CURSOR (ee) -3-3 -3-5 -7-8 -20
CURSOR (ee) Frame material (h) Chisel indexes Adjustable glass Window corners Tension Spring Digit registering Hook index for edge log-log scales BOX Nickel plated brass Aluminium Nickel silver 2 each on left & right edges With 2 mm screws With 1 mm screws Rounded Square cut Present (centre riveted) With 2 domed rivets With 1 domed & 1 flat rivet With 2 flat rivets Top edge Bottom edge -3-3 -3 367, 377, 380-3 -3-3 -5 16. -5-7 367,, 377, 380-7 -8-8 -20 343-20 Cross-section (ff) Rectangular 50 cm scale Flattened rectangular with rounded edges not 50 cm scale Brand text on front (gg) Oval Arched script not 50 cm scale 'Rechenstab ' Small block Back label style (hh) Style A Style B Style C Style D Back label awards 'Paris ' exhibition 'St.Louis ' exhibition Back label medals text 'Gold and First-class Prize Medals.' Model number label (ff) 'Prize Medals from all important exhibitions.' No border Broken border Solid border Formatting: Generic Specific Not known Crossover Overlap in change points
Additional model and type notes 1. 354, 355, 357, 363, 364, 367 16. 367, 377, 380 2. 354, 355, 357, 363, 364, 365, 367,, 374, 377, 378 17. 350, 355, 360, 361, 363 3. 354, 355, 357, 363, 364, 365, 367, 374, 377, 378 18. 350, 355, 361, 363 4. not 12.5 cm scale or 366 19. 363, 364, 367 5. 12.5 cm scale & 366 20. 354, 357 6. not 361, 21. 50 cm scale & 363, 364, 365, 367,, 374, 377 7. not 361 22. 50 cm scale & 363, 364, 365, 367, 374, 377, 378 8. non- 23. 50 cm scale & 363, 364, 367, 374, 377, 378 9. 364, 367 24. 50 cm scale & 360, 363, 364, 367, 374, 377, 378 10. or 12.5 or 50 cm scale or 361, 366 25. 50 cm scale & 354, 357, 360, 363, 364, 367, 374, 377, 378 11. not 12.5 or 50 cm scale or 366 26. 354, 357, 363, 364, 367,, 374, 377, 380 12. 27. 354, 357, 364, 367,, 374, 377, 380 13. or 12.5 or 50 cm scale or 366 28. 354, 357, 363, 364, 367, 374, 377, 380 14. or 12.5cm scale or 361, 366 29. 354, 357, 364, 367, 374, 377, 380 15. or 12.5 or 50 cm scales or 361, 366, * 369 possible flat or rebate back Model number identification c- (before printed on slide rule) Model Not faced < 28 cm stock 350 28 cm stock Normal cursor 354 357 50 cm scale Caliper cursor 358 370 Celluloid faced 15.5 cm scale 369 26 cm stock No slide springs 360 Slide springs 365 28-29 cm stock Scale on back of stock Normal cursor 374 377 No scale on Numbers with No SLT scales 361 back of stock decimal point SLT scales 363 Numbers No scales on back of slide 366 without Scales on back Log-log scales on edge decimal point of slide No log-log scales on edge Normal cursor 364 367 50 cm scales 380 Feature notes (a) All stocks in this timeframe were made from wood. Initially the two stock rails and well were formed from one solid piece. Two (e) Ticks are the small extensions to the division marks which extend beyond the railway track lines. See also (aa). longitudinal slits were introduced into the well that usually penetrate both the solid wooden stock (which may be covered on the (f) Identification numbers of the subdivisions on the Mannheim scales between the major divisions of 1, 2, 3 etc. are either Decimal back with a paper label) and the celluloid facing in the well (if present), occasionally they are only in the wood. A two piece notation (eg 1.2, 1.2, 1.3 etc) or Non-decimal notation (eg 1, 2, 3 etc.). In the decimal notation the 1.5 and 15 numbers were celluloid sprung stock is distinguished by an end-to-end longitudinal split in the wood of the well of the stock with no initially displaced on the A and B scales compared to the rest of the subdivision numbers. See also (aa). corresponding split in the celluloid facing in the well. A steel sprung stock is distinguished by an end-to-end longitudinal split in (g) Identification numbers for the divisions on the Mannheim scales were initially printed by hand one digit at a time and both the wood and thethe celluloid facing (if present) of the well. consequently show some variation in the alignment of the digits. Subsequently the numbers were printed using a template (b) Cursor grooves will either: split an edge ruler (numbers above groove and divisions below) and be perpendicular to the edge face; giving a more uniformly aligned appearance. See also (aa) be entirely above a ruler and parallel to the top face of the rule; be angled into the stock at the join of the top and edge faces. (h) Nickel plated brass and nickel silver cursors are heavy and shiny (if the plating has not worn off) compared to aluminium cursors. (c) Slide is slightly shorter than stock with an aluminium index edge for reading the scales in the well. Worn plated cursors will show an underlying brass colour. Plated cursors are slightly magnetic, nickel silver cursors are not. (d) Hand printed scales are smooth on the face of the rule and exhibit random marking differences from being drawn from a pattern. Template printed scales are also smooth, but differences are consistent. Lightly incised scales show a faint texture when a fingernail is drawn across the marks. Deeply incised scales show an obvious texture when a fingernail is drawn across the marks. (aa) Scale formats (ee) Cursor examples Plain scales, decimal notation, hand printed numbers typeface A, displaced 1.5 Unequal double line railway track scales, no ticks, decimal notation, hand printed numbers typeface A, displaced 1.5 Double line railway track scales, ticks, non-decimal notation, template printed numbers typeface B, arrow ± symbols Single line railway track scales, ticks, nondecimal notation, template printed numbers typeface C, arrow ± symbols Nickel plated brass, chisels, 2 mm adjusting screws, rounded window, no spring Aluminium, digit registering with 2 domed rivets, rounded window, centre riveted spring Aluminium, hook index, square cut window, centre riveted spring (cc) Script M gauge mark (dd) Slide rule back label text style (ff) Box profile and model label A. With tails B. Without tails Square box, label with no Square box, label with Flat box with rounded Oval box, label with solid border
(bb) Slide rule back style label examples 1. (gg) Box brand text 2. (large text) Arched scipt 'Rechenstab...' Small block (hh) Box back label style examples A. (gold on black) 3. (small text) 4. (large text) B. (gold on black or black on white) 5. (small text) C. (red & green text) 6. French C. Non- (green & red text) 7. Electro D. (with care instrucions) 8. Non- Electro D. Non- (with care instrucions) In/cm conversion scale Advertising