7
August 2017 - 1 - Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920 Colin Tombeur Background This article is one of a series which details the early slide rules of A.W. Faber-Castell (hereafter referred to as Faber). The series, by Trevor Catlow and myself, is based on our research collaboration and the resulting development and analysis of a database of slide rule specimens, as described in [1]. Although Faber began production with just one known slide rule model, they quickly developed their designs, production processes and model range. Due the scarcity of detailed reliable information, dating these slide rules before Faber introduced blind date stamps has been difficult. Trevor’s 2009 JOS article [2] and subsequent 2013 update [3] were the first major steps in rectifying this situation. Although broadly correct, Trevor’s findings were based largely on the limited number of slide rules from this time in his collection. As a result his scope was limited, a fact that he acknowledged in his articles. Our collaboration has produced a more comprehensive chronology of changes to features on these early slide rules, based on the study of many more specimens, cataloguing and dating as many changes as possible. This article gives an overview of feature changes between the beginning of slide rule production in 1892 [4] and the introduction of date stamps on the rules in 1920 [5]. We have been able to supply an approximate year, or span of years, for the changes, which we believe to be accurate to within a year or so. Planned further articles in the series will describe particular areas of focus and the chronology of feature changes in much greater detail. A slide rule can only be as old as the introduction of its most recent feature, and as young as the earliest time a feature present on it was phased out. [1] A slide rule without a blind stamp can be given an approximate date range of the completion of its manufacture by comparing and aligning its features with the Chronology Chart below. In theory all of the date ranges of features on a specimen should overlap at some point on the chart and an approximate date of manufacture can easily be established. Occasionally however, due to peculiarities in the design and manufacturing process this is not the case, but a manufacture date can still be estimated using the above guideline from the latest overlapping range of features. Particular care should be taken when considering cursors and boxes which may have been replaced with non-original items. Unless a definite connection can be established, for example by the addition of names or dates by a previous owner, these items should be considered as confirming, rather than defining, the dating. Introducing the Chronology Chart The Chronology Chart has rows detailing slide rule features, grouped into the following five categories: STOCK & SLIDE, SCALES, CURSOR, TEXT & LABELS and BOX. Each feature may have several manifestations. Some of the features have references to chart notes, either a single character for further description, e.g. (a), or two characters for picture examples, e.g. (aa). The columns indicate an approximate year, or year range, when a change occurred, ‘Change Point’, prefixed with ‘c’ (circa). Where it has not been possible to define change points unambiguously for certain features, some year ranges overlap others. Such cases are highlighted in light blue, and special care should be taken when comparing features around these points. In the main body of the chart, features that are present at the change points are indicated by solid green shading. Thus an approximate start point, when the feature first appeared on slide rules, and end point (unless it was ongoing after 1920), when it was phased out, can be determined for each feature. Orange shading indicates an unknown status, where there is insufficient or no evidence to determine whether a feature was present or not. The green shading is either dark, indicating a generic presence across all slide rules

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Page 1: Overview of A.W. Faber-Castell Slide Rule Dating ...Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920 - 2 - current at that time, or one of two lighter shades,

August 2017

- 1 -

Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

Colin Tombeur

Background This article is one of a series which details the early slide rules of A.W. Faber-Castell (hereafter referred to as Faber). The series, by Trevor Catlow and myself, is based on our research collaboration and the resulting development and analysis of a database of slide rule specimens, as described in [1]. Although Faber began production with just one known slide rule model, they quickly developed their designs, production processes and model range. Due the scarcity of detailed reliable information, dating these slide rules before Faber introduced blind date stamps has been difficult. Trevor’s 2009 JOS article [2] and subsequent 2013 update [3] were the first major steps in rectifying this situation. Although broadly correct, Trevor’s findings were based largely on the limited number of slide rules from this time in his collection. As a result his scope was limited, a fact that he acknowledged in his articles. Our collaboration has produced a more comprehensive chronology of changes to features on these early slide rules, based on the study of many more specimens, cataloguing and dating as many changes as possible. This article gives an overview of feature changes between the beginning of slide rule production in 1892 [4] and the introduction of date stamps on the rules in 1920 [5]. We have been able to supply an approximate year, or span of years, for the changes, which we believe to be accurate to within a year or so. Planned further articles in the series will describe particular areas of focus and the chronology of feature changes in much greater detail.

A slide rule can only be as old as the introduction of its most recent feature, and as young as

the earliest time a feature present on it was phased out. [1] A slide rule without a blind stamp can be given an approximate date range of the completion of its manufacture by comparing and aligning its features with the Chronology Chart below. In theory all of the date ranges of features on a specimen should overlap at some point on the chart and an approximate date of manufacture can easily be established. Occasionally however, due to peculiarities in the design and manufacturing process this is not the case, but a manufacture date can still be estimated using the above guideline from the latest overlapping range of features. Particular care should be taken when considering cursors and boxes which may have been replaced with non-original items. Unless a definite connection can be established, for example by the addition of names or dates by a previous owner, these items should be considered as confirming, rather than defining, the dating. Introducing the Chronology Chart The Chronology Chart has rows detailing slide rule features, grouped into the following five categories: STOCK & SLIDE, SCALES, CURSOR, TEXT & LABELS and BOX. Each feature may have several manifestations. Some of the features have references to chart notes, either a single character for further description, e.g. (a), or two characters for picture examples, e.g. (aa). The columns indicate an approximate year, or year range, when a change occurred, ‘Change Point’, prefixed with ‘c’ (circa). Where it has not been possible to define change points unambiguously for certain features, some year ranges overlap others. Such cases are highlighted in light blue, and special care should be taken when comparing features around these points. In the main body of the chart, features that are present at the change points are indicated by solid green shading. Thus an approximate start point, when the feature first appeared on slide rules, and end point (unless it was ongoing after 1920), when it was phased out, can be determined for each feature. Orange shading indicates an unknown status, where there is insufficient or no evidence to determine whether a feature was present or not. The green shading is either dark, indicating a generic presence across all slide rules

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Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 2 -

current at that time, or one of two lighter shades, indicating that the presence is specific to a certain set of slide rules. Where the presence is specific, the set is indicated inside the shading either with text or, when there is insufficient space, as a reference to a one or two digit chart note (e.g. 10.). Sets are generally models (e.g. ‘350, 360, 365’), model exclusions (e.g. ‘not 350, 360, 365’), languages (e.g. ‘German’, ‘non-German’) or models of certain scale length or construction (e.g. ’50 cm scale’, ‘not 50 cm scale’, ‘all-wood’, ‘not all-wood’). While it is possible to use the chart for dating without knowing a model number, it is easier if the model is known. If present, the model number is the three digit number on the front of the slide rule before the maker’s name. If this number is not present, the model can be quickly established using the guide at the end of this article. Referring to the first few rows of the Chronology Chart, examples of the above conventions for representing specific changes can be seen. In row 1, it is shown that a 15 cm stock length is found only on models with a 12.5 cm scale length, from c1907-8 onwards. Row 2 shows that a 26.4 cm stock was seen only in c1892. The dark green colouration of this cell indicates that “all current models” were of this length (even though in fact only one model actually existed at the time). Row 3 shows that the generic stock length changed to 26 cm in c1892-3. Row 4 shows that stocks with a length of 28 cm were introduced in c1899 for the six models indicated. Referring back to row 3, the 26 cm stock length is no longer generic but specific to models 350, 360 and 365 from this time until c1909 (although this does not define the date of the introduction of these models, see below). In c1907, note 1 indicates that a different subset of models had the 28cm stock, and this subset changed again in c1910. Row 5 shows that the model 368 had a 28.5 cm stock between c1907 and c1910-11. As previously indicated, the dates of the change points are approximate to within a year or so, however some features are known to crossover around specific years, particularly those involving registered designs and patents. In this case, the shading is crosshatched to indicate a possible presence or not in the change point, or a transition to an unknown status. In addition, crosshatching is used where there is potential ambiguity due to an overlap in change points (those highlighted in blue). For example, “Cursor grooves – above both top and bottom edge rulers”. This feature was true of all slide rules from c1903-4 ongoing, with the exception of the 368 from c1906 to c1910-11 when it was withdrawn. Therefore from c1903-4 up to c1906 and from c1911 to the end, this feature is coloured dark green (generic), and the chronological points in-between, c1906 to c1910-11, are light green (specific) with the model 368 indicated. The overlap change points c1908-13, c1910-12 and c1910-13 are crosshatched light and dark green to indicate a crossover in these periods. The chronology is necessarily complex because features can be specific to certain sets of slide rules, or there can be different evolutionary timescales for a particular feature for different sets of rules. In order to simplify, the model specific notes do not necessarily indicate exactly when models were introduced, since this is often unclear. Therefore, generally, the chronology should not be used for this purpose [6]. However some models were introduced with dateable model defining features, for example the 360 with the introduction of celluloid scales, the 367 with its digit registering cursor, and the 368 ‘electro’ model. Our chronology does not claim to be definitive, but Trevor and I believe we have reached a point of stability in our findings. Nevertheless, if any of our readers can provide additional information, please do contact us, our details can be found in the UKSRC membership directory. Assigning Model Numbers to Faber Slide Rules From c1908 to well after 1920 Faber slide rules carried a three digit model number, beginning with a ‘3’, and followed by a ‘*’ before the maker’s name, for example “368 * A.W. FABER.”. Before this, model numbers did not appear on the slide rules themselves although they are known to have existed, appearing in manuals and catalogues, from around 1895 [7]. It is unclear if the very first slide rules made between 1892 and 1895 were assigned model numbers, but examples show marked similarities to the model identified as the 350 in 1895, so for the purpose of identification these first slide rules are also considered as the model 350. For the seventeen models that were in production between 1892 and c1908, and therefore did not carry a model number, this guide enables the number to be determined. Using Table 1 it is easy to identify the model

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Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 3 -

from a few obvious features. Some details of these models changed over time (for example the model 360 changed from a 26 cm length to a 28 cm length) but only after model numbers appeared on them. For certain models the guide depends on the fact that models originating with digital-registering cursors have not lost them. As a check, these rules carried the label ‘DRGM 116832’ until c1905. Starting at the left-hand side of the table, compare the features listed at each stage until reaching the model number at the right-hand side. Features at each stage are mutually exclusive. For example, is the slide rule faced or not faced? If it is not faced, then is the stock less than 28 cm, equal to 28 cm or is the scale 50 cm? If it is 28 cm then is the cursor normal, digit registering or a calliper? If the cursor is digit registering then the slide rule is a model 357.

References & Bibliography [1] Every Slide Rule Tells a Story - Establishing an Early A.W. Faber-Castell Chronology (Colin Tombeur),

United Kingdom Slide Rule Circle (UKSRC), Slide Rule Gazette, Issue 17, Autumn 2017, Page 15 [2] Suggestions for Dating pre-1920 Faber-Castell Slide Rules (Trevor Catlow), Journal of the Oughtred

Society, 18.2, Fall 2009, Page 47 [3] Suggestions for Dating pre-1920 Faber-Castell Slide Rules: an Update (Trevor Catlow), Journal of the

Oughtred Society, 22.1, Spring 2013, Page 45 [4] Slide Rules: A Journey through Three Centuries (Dieter von Jezierski), Astragal Press, 2000 [5] Rechenschieber Slide Rules A.W. Faber A.W. Faber-Castell (Peter Holland), self-publication [6] For a comprehensive compendium of the dates of Faber slide rule models, see [5]. Due to differences in

methodology, dates in this book do not always agree with those in this article. This dating business is not (yet) a fully-defined science, see also [1].

[7] Transition from boxwood to celluloid on boxwood within A.W. Faber (Dieter von Jezierski), United Kingdom Slide Rule Circle (UKSRC), Skid Stick, No. 11, June 2002, Page 7

The Chronology Chart is available in larger printer friendly formats on the UKSRC web site in the Gaz Plus section (uksrc.org.uk/gazplus.html), Gazette 2017 Vol 17, Supplemental Material. A full bibliography of sources used in the development of this article can be found in [1].

Model

350

354

357

358

370

369

360

365

374

377

361

363

366

368

Normal cursor 364

Digit registering cursor 367

380

Not faced

28 cm stock

Celluloid faced

26 cm stock

28-29 cm stock

< 28 cm stock

Normal cursor

Digit registering cursor

Normal cursorScale on back of

stock

No scale on

back of stock

Numbers with

decimal point

Numbers

without decimal

point

Scales on back

of slide

Digit registering cursor

No SLT scales

SLT scales

No scales on back of slide

Table 1 : Faber model identification 1892-c1908

Caliper cursor

50 cm scale

15.5 cm scale

No slide springs

Slide springs

Log-log scales on edge

50 cm scales

No log-log

scales on edge

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Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 4 -

CHRONOLOGY CHART

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

12

.5 c

m s

cale

35

0, 3

60

, 36

5

35

4, 3

57

, 36

3, 3

64

, 36

7, 3

68

1.

no

t 1

2.5

or

50

cm

sca

le o

r 3

68

, 37

8

36

8

37

8

50

cm

sca

le

no

t 3

69

all

-wo

od

no

t a

ll-w

oo

d

no

n-G

erm

an

36

1, 3

66

, 36

9*,

37

4, 3

77

, 37

9, 3

84

Ge

rma

nn

ot

36

1, 3

66

, 36

9*,

37

4, 3

77

, 37

9, 3

84

36

1, 3

66

, 36

8

no

t 3

61

, 36

6, 3

68

no

t 3

68

36

8

36

8

36

1

no

t 3

61

no

t 3

61

, 36

6

no

t 3

50

, 36

0, 3

65

no

t 3

61

, 36

6

no

t a

ll-w

oo

d

no

t a

ll-w

oo

d o

r 3

61

no

t a

ll-w

oo

d

35

4, 3

57

, 36

3, 3

64

, 36

5, 3

67

2.

3.

36

5, 3

78

36

8, 3

78

, 37

9

no

t a

ll-w

oo

d

no

t a

ll-w

oo

d no

t a

ll-w

oo

d o

r 1

2.5

cm

sca

le

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

36

93

69

, 37

9

no

t 3

69

, 37

9, 3

80

, 38

4

38

03

80

, 38

4

op

tio

n o

n 3

60

, 36

3, 3

64

, 36

5, 3

67

all

-wo

od

& 5

0 c

m s

cale

4.

no

t a

ll-w

oo

d o

r 5

0 c

m s

cale

s5

.

all

-wo

od

all

-wo

od

no

t a

ll-w

oo

d

no

t 3

68

6.

7.

36

83

61

, 36

6

no

t 3

61

, 36

6, 3

68

no

t 5

0 c

m s

cale

or

36

1, 3

66

, 36

8, 3

74

, 37

7, 3

78

8.

38

0

8.

Pla

in (n

o r

ail

wa

y tr

ack

s)

Rig

ht

en

d (s

in &

log

sca

les)

Left

en

d (t

an

sca

les)

On

ba

ck o

f sto

ck

On

ba

ck o

f sto

ck a

lign

ed

to

rig

ht

slo

t in

de

x

Top

ed

ge, n

ot

to e

nd

s o

f sto

ck

Bo

tto

m e

dge

no

t to

en

ds

of s

tock

Bo

tto

m e

dge

to

en

ds

of s

tock

On

ba

ck o

f sli

de

In w

ell

Ce

nti

me

tre

ext

en

sio

n

sca

le

Inch

/ce

nti

me

tre

con

vers

ion

sca

le (b

b)

A.W

. FA

BER

-CA

STEL

L SL

IDE

RU

LE F

EATU

RES

18

92

-19

20

STO

CK

& S

LID

E

15

cm

26

cm

26

.4 c

m

28

cm

28

.5 c

m

29

.5 c

m

53

.5 c

m

Ab

ove

to

p e

dge

ru

ler

bu

t sp

lit

bo

tto

m e

dge

ru

ler

Ab

ove

bo

th t

op

& b

ott

om

ed

ge r

ule

rs

An

gle

d in

to s

tock

at

fro

nt/

top

ed

ge jo

in

An

gle

d in

to s

tock

at

fro

nt/

bo

tto

m e

dge

join

Rig

ht

en

d o

f fro

nt

Fla

t b

ack

(no

re

ba

te a

nd

ta

ble

s)

Re

ba

ted

wit

h p

ap

er

tab

les

At

bo

tto

m o

f sli

de

ed

ge

In c

en

tre

of s

lid

e e

dge

Me

tal i

nse

rts

Form

at

of M

an

nh

eim

sca

les

(aa

)

Ch

ise

l in

de

x fo

r w

ell

sca

les

Sto

ck

Sin

gle

ra

ilw

ay

tra

ck

Un

eq

ua

l do

ub

le r

ail

wa

y tr

ack

Do

ub

le r

ail

wa

y tr

ack

Slid

e

Lon

gitu

din

al i

n s

tock

& s

lid

e

SCA

LES

15

cm

Slid

e in

de

x e

nd

(c)

Wo

od

en

fixi

ng

pin

s fo

r

cell

ulo

id

25

cm

Ha

nd

pri

nte

d s

cale

s

Tem

pla

te p

rin

ted

sca

les

Ligh

tly

inci

sed

sca

les

De

ep

ly in

cise

d s

cale

s

Up

pe

r st

ock

ra

il, b

elo

w s

lid

e g

roo

ve

Up

pe

r st

ock

ra

il, i

n s

lid

e g

roo

ve

Sca

le le

ngt

h

Ch

ange

Po

int

Ma

rkin

g m

eth

od

(d)

Ru

lers

on

ed

ges

Spli

t b

oth

ed

ge r

ule

rs

Top

& b

ott

om

ed

ges

25

.2 c

m (a

pp

rox.

)

Len

gth

Sto

ck c

on

stru

ctio

n (a

)

Ba

ck o

f sto

ck

Bo

tto

m e

dge

of s

tock

Cu

rso

r gr

oo

ves

(b)

Slid

e T

hu

mb

No

tch

Slid

e r

un

ne

r

Slo

ts in

ba

ck o

f sto

ck t

o

ind

ex

ba

ck o

f sli

de

Ce

llu

loid

faci

ngs

Bo

xwo

od

sp

rin

gs t

o

ten

sio

n s

lid

e

Sin

gle

pie

ce, s

oli

d

Sin

gle

pie

ce w

ith

2 lo

ngi

tud

ina

l sli

ts in

we

ll

Two

pie

ce, c

ell

ulo

id s

pru

ng

Two

pie

ce, s

tee

l sp

run

g

Be

vell

ed

Pe

rpe

nd

icu

lar

Fro

nt,

we

ll &

fro

nt

& b

ack

of s

lid

e

50

cm

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Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 5 -

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

no

t 3

61

36

79

.a

ll-w

oo

d

all

-wo

od

10

.n

ot

all

-wo

od

or

12

.5 o

r 5

0 c

m s

cale

or

36

61

1.

12

.

13

.

14

.n

ot

12

.5cm

sca

le o

r 3

66

36

8, 3

78

, 37

9

36

8, 3

78

, 37

9

36

8, 3

78

, 37

9

15

.

36

8

36

8, 3

78

, 37

9

37

4, 3

77

36

6

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

no

n-E

ngl

ish

no

n-E

ngl

ish

all

-wo

od

& 5

0 c

m s

cale

no

n-E

ngl

ish

all

-wo

od

Engl

ish

Engl

ish

all

-wo

od

& 5

0 c

m s

cale

Engl

ish

all

-wo

od

no

t a

ll-w

oo

d o

r 5

0 c

m s

cale

no

t a

ll-w

oo

d

35

0, 3

55

, 36

0, 3

61

, 36

3, 3

65

35

0, 3

55

, 36

1, 3

63

17

.1

8.

all

-wo

od

no

t a

ll-w

oo

da

ll-w

oo

d

no

t a

ll-w

oo

d

36

3, 3

67

19

.3

54

, 35

72

0.

50

cm

sca

le &

36

3, 3

64

, 36

7, 3

68

, 37

4, 3

77

21

.2

2.

23

.2

4.

25

.

36

3, 3

67

26

.2

7.

28

.3

63

29

.

`

36

8, 3

78

, 37

9

36

8

no

t a

ll-w

oo

d

no

t a

ll-w

oo

d o

r 1

2.5

cm

sca

le

36

6

37

4, 3

77

37

4, 3

77

Ge

rma

n

Ge

rma

n

Ge

rma

n, n

ot

36

8, 3

69

, 37

8, 3

79

Engl

ish

Engl

ish

, no

t 3

68

, 36

9, 3

78

, 37

9

Styl

e 6

(Fre

nch

)Fr

en

ch, n

ot

36

8, 3

69

, 37

8, 3

79

36

8, 3

78

36

93

69

36

9

Ge

rma

n

No

n-G

erm

an

'DR

P 2

06

42

8' (

19

08

)

Styl

e 2

(Ge

rma

n)

'DR

P 2

15

72

2' (

19

09

)

Ba

ck la

be

l sty

le (b

b)

Ba

ck la

be

l te

xt s

tyle

(dd

)

Ba

ck a

dve

rtis

ing

lab

el

(bb

)

Pa

pe

r

Ce

llu

loid

Styl

e 4

(En

glis

h)

Styl

e 7

(En

glis

h e

lect

ro),

8 (N

on

-En

glis

h e

lect

ro)

Styl

e A

Styl

e B

Styl

e 5

(En

glis

h)

Tem

pla

te p

rin

ted

'Qu

ot.

+1' &

'Pro

d.-

1'

On

left

& r

igh

t u

pp

er

sto

ck e

nd

s

3-d

igit

, fo

llo

we

d b

y '*

' be

fore

bra

nd

Bo

xwo

od

sp

rin

gs in

we

ll fo

r sl

ide

Dig

it r

egi

ste

rin

g cu

rso

r

Syst

em

Pic

kwo

rth

Syst

em

Pic

kwo

rth

Styl

e 1

(Ge

rma

n)

Slid

e e

nd

ind

ex

ed

ge fo

r w

ell

sca

les

Cu

rso

r w

ith

ho

ok

ind

ex

for

ed

ge s

cale

s

Wo

od

fixi

ng

pin

s fo

r ce

llu

loid

Lon

gitu

din

al m

eta

l in

sert

s

Syst

em

Sch

um

ach

er

No

n-E

ngl

ish

/no

n-G

erm

an

lan

gua

ge r

ule

s

'QU

OTI

ENT

+1' &

'PR

OD

UC

T -1

'

De

cim

al n

ota

tio

n

Dis

pla

ced

1.5

/15

on

A &

B s

cale

s

Styl

e A

Styl

e B

Styl

e C

SCA

LES

(co

nti

nu

ed

)

SLT

sca

les

On

ba

ck o

f sli

de

On

A, B

, C &

D

Tick

s o

n M

an

nh

eim

sca

les

(e)

'DR

GM

37

11

90

' (1

90

8)

Bra

nd

typ

efa

ce

Ha

nd

pri

nte

d

Engl

ish

lan

gua

ge r

ule

s

Qu

oti

en

t/P

rod

uct

± o

n

low

er

sto

ck e

nd

s

Ele

ctro

ga

uge

ma

rks

c &

c1

ga

uge

ma

rks

On

A &

B o

nly

'DR

GM

34

45

76

' (1

90

8)

'DR

GM

37

11

89

' (1

90

8)

Scri

pt

M (w

ith

lon

g ta

il) o

n B

on

lyM

ga

uge

ma

rk (c

c)

Log-

log

ind

ex

ma

rks

Syst

em

Pic

kwo

rth

Syst

em

Sch

um

ach

er

Bra

nd

na

me

Nu

mb

ers

on

sca

le

sub

div

isio

ns

(f)

Sca

le n

um

be

rin

g

typ

efa

ce (a

a)

Sca

le n

um

be

rin

g

ma

rkin

g (g

)

Arr

ow

± s

ymb

ols

(aa

)

Mo

de

l nu

mb

er

'DR

GM

98

35

0' (

18

98

)

'DR

GM

11

68

32

' (1

89

9)

'DR

GM

42

75

14

' (1

90

5)

'DR

GM

27

11

69

' (1

90

6)

W o

n r

igh

t e

nd

of C

Cu

be

sca

le a

nd

win

do

w o

n b

ack

of s

tock

No

n-l

oga

rith

mic

sca

les

an

d in

de

xes

TEX

T &

LA

BEL

S

On

D a

s w

ell

as

C

"Dyn

am

o"/

"Mo

tor"

& "

Vo

lt"

sca

les

in w

ell

Me

tric

(28

7 &

73

6 o

n A

& B

sca

les)

Imp

eri

al (

28

7 &

74

6 o

n A

& B

sca

les)

Un

lab

ell

ed

on

no

n-e

lect

ro r

ule

s

Ele

ctro

sca

les

Styl

e 3

(Ge

rma

n)

Ori

gin

('M

AD

E IN

…')

'A.W

. Fa

be

r'

'A.W

. Fa

be

r "C

ast

ell

"'

Go

ld s

eri

f

Go

ld s

an

s-se

rif

Bla

ck s

an

s-se

rif

2.9

on

left

& r

igh

t e

nd

s o

f D

San

s-se

rif M

on

A &

B

Scri

pt

M (w

ith

lon

g ta

il) o

n A

& B

Seri

f M o

n A

& B

Page 6: Overview of A.W. Faber-Castell Slide Rule Dating ...Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920 - 2 - current at that time, or one of two lighter shades,

Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 6 -

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

34

3

36

7, 3

77

, 38

0

16

.

36

7, 3

68

, 37

7, 3

80

36

8

36

8

c1892

c1892-3

c1893-5

c1895

c1896-9

c1898-9

c1899

c1900

c1900-3

c1901

c1901-3

c1903

c1903-4

c1904

c1904-5

c1905

c1905-6

c1906

c1906-7

c1907

c1907-8

c1908

c1908-9

c1908-13

c1909

c1910

c1910-11

c1910-12

c1910-13

c1911

c1912

c1912-13

c1913

c1914

c1914-20

50

cm

sca

le

no

t 5

0 c

m s

cale

no

t 5

0 c

m s

cale

Engl

ish

Ge

rma

n

Engl

ish En

glis

h

Engl

ish

Engl

ish

Ch

art

No

tes

(re

fer

to t

ext

for

mo

re d

eta

il):

Ge

ne

ric

Spe

cifi

cN

ot

kno

wn

(a

)A

ll s

tock

s in

th

is t

ime

fra

me

we

re m

ad

e fr

om

wo

od

. In

itia

lly

the

tw

o s

tock

ra

ils

an

d w

ell

we

re fo

rme

d fr

om

on

e s

oli

d p

iece

. Tw

o

lon

gitu

din

al s

lits

we

re in

tro

du

ced

into

th

e w

ell

th

at

usu

all

y p

en

etr

ate

bo

th t

he

so

lid

wo

od

en

sto

ck (w

hic

h m

ay

be

co

vere

d o

n t

he

Cro

sso

ver

Ove

rla

p in

ch

an

ge p

oin

tsb

ack

wit

h a

pa

pe

r la

be

l) a

nd

th

e c

ell

ulo

id fa

cin

g in

th

e w

ell

(if p

rese

nt)

, occ

asi

on

all

y th

ey

are

on

ly in

th

e w

oo

d.

A t

wo

pie

ce

cell

ulo

id s

pru

ng

sto

ck is

dis

tin

guis

he

d b

y a

n e

nd

-to

-en

d lo

ngi

tud

ina

l sp

lit

in t

he

wo

od

of t

he

we

ll o

f th

e s

tock

wit

h n

o

corr

esp

on

din

g sp

lit

in t

he

ce

llu

loid

faci

ng

in t

he

we

ll.

A s

tee

l sp

run

g st

ock

is d

isti

ngu

ish

ed

by

an

en

d-t

o-e

nd

lon

gitu

din

al s

pli

t in

1.

35

4, 3

55

, 35

7, 3

63

, 36

4, 3

67

16

.3

67

, 37

7, 3

80

bo

th t

he

wo

od

an

d t

he

the

ce

llu

loid

faci

ng

(if p

rese

nt)

of t

he

we

ll.

2.

35

4, 3

55

, 35

7, 3

63

, 36

4, 3

65

, 36

7, 3

68

, 37

4, 3

77

, 37

81

7.

35

0, 3

55

, 36

0, 3

61

, 36

3

(b)

Cu

rso

r gr

oo

ves

wil

l eit

he

r: s

pli

t a

n e

dge

ru

ler

(nu

mb

ers

ab

ove

gro

ove

an

d d

ivis

ion

s b

elo

w) a

nd

be

pe

rpe

nd

icu

lar

to t

he

ed

ge fa

ce;

3.

35

4, 3

55

, 35

7, 3

63

, 36

4, 3

65

, 36

7, 3

74

, 37

7, 3

78

18

.3

50

, 35

5, 3

61

, 36

3b

e e

nti

rely

ab

ove

a r

ule

r a

nd

pa

rall

el t

o t

he

to

p fa

ce o

f th

e r

ule

; be

an

gle

d in

to t

he

sto

ck a

t th

e jo

in o

f th

e t

op

an

d e

dge

face

s.

4.

no

t 1

2.5

cm

sca

le o

r 3

66

19

.3

63

, 36

4, 3

67

(c

)Sl

ide

is s

ligh

tly

sho

rte

r th

an

sto

ck w

ith

an

alu

min

ium

ind

ex

ed

ge f

or

rea

din

g th

e s

cale

s in

th

e w

ell

.

5.

12

.5 c

m s

cale

& 3

66

20

.3

54

, 35

7

(d)

Ha

nd

pri

nte

d s

cale

s a

re s

mo

oth

on

th

e fa

ce o

f th

e r

ule

an

d e

xhib

it r

an

do

m m

ark

ing

dif

fere

nce

s fr

om

be

ing

dra

wn

fro

m a

pa

tte

rn.

6.

no

t 3

61

, 36

82

1.

50

cm

sca

le &

36

3, 3

64

, 36

5, 3

67

, 36

8, 3

74

, 37

7Te

mp

late

pri

nte

d s

cale

s a

re a

lso

sm

oo

th, b

ut

dif

fere

nce

s a

re c

on

sist

en

t. L

igh

tly

inci

sed

sca

les

sho

w a

fain

t te

xtu

re w

he

n a

7.

no

t 3

61

22

.5

0 c

m s

cale

& 3

63

, 36

4, 3

65

, 36

7, 3

74

, 37

7, 3

78

fin

gern

ail

is d

raw

n a

cro

ss t

he

ma

rks.

De

ep

ly in

cise

d s

cale

s sh

ow

an

ob

vio

us

text

ure

wh

en

a fi

nge

rna

il is

dra

wn

acr

oss

th

e m

ark

s.

8.

no

n-G

erm

an

23

.5

0 c

m s

cale

& 3

63

, 36

4, 3

67

, 37

4, 3

77

, 37

8

(e)

Tick

s a

re t

he

sm

all

ext

en

sio

ns

to t

he

div

isio

n m

ark

s w

hic

h e

xte

nd

be

yon

d t

he

ra

ilw

ay

tra

ck li

ne

s. S

ee

als

o (a

a).

9.

36

4, 3

67

24

.5

0 c

m s

cale

& 3

60

, 36

3, 3

64

, 36

7, 3

74

, 37

7, 3

78

(f

)Id

en

tifi

cati

on

nu

mb

ers

of t

he

su

bd

ivis

ion

s o

n t

he

Ma

nn

he

im s

cale

s b

etw

ee

n t

he

ma

jor

div

isio

ns

of 1

, 2, 3

etc

. are

eit

he

r D

eci

ma

l

10

.n

ot

all

-wo

od

or

12

.5 o

r 5

0 c

m s

cale

or

36

1, 3

66

25

.5

0 c

m s

cale

& 3

54

, 35

7, 3

60

, 36

3, 3

64

, 36

7, 3

74

, 37

7, 3

78

no

tati

on

(eg

1.2

, 1.2

, 1.3

etc

) o

r N

on

-de

cim

al n

ota

tio

n (e

g 1

, 2, 3

etc

.). I

n t

he

de

cim

al n

ota

tio

n t

he

1.5

an

d 1

5 n

um

be

rs w

ere

11

.n

ot

12

.5 o

r 5

0 c

m s

cale

or

36

62

6.

35

4, 3

57

, 36

3, 3

64

, 36

7, 3

68

, 37

4, 3

77

, 38

0in

itia

lly

dis

pla

ced

on

th

e A

an

d B

sca

les

com

pa

red

to

th

e r

est

of t

he

su

bd

ivis

ion

nu

mb

ers

. Se

e a

lso

(aa

).

12

.a

ll-w

oo

d2

7.

35

4, 3

57

, 36

4, 3

67

, 36

8, 3

74

, 37

7, 3

80

(g

)Id

en

tifi

cati

on

nu

mb

ers

for

the

div

isio

ns

on

th

e M

an

nh

eim

sca

les

we

re in

itia

lly

pri

nte

d b

y h

an

d o

ne

dig

it a

t a

tim

e a

nd

13

.n

ot

all

-wo

od

or

12

.5 o

r 5

0 c

m s

cale

or

36

62

8.

35

4, 3

57

, 36

3, 3

64

, 36

7, 3

74

, 37

7, 3

80

con

seq

ue

ntl

y sh

ow

so

me

va

ria

tio

n in

th

e a

lign

me

nt

of t

he

dig

its.

Su

bse

qu

en

tly

the

nu

mb

ers

we

re p

rin

ted

usi

ng

a t

em

pla

te

14

.n

ot

all

-wo

od

or

12

.5cm

sca

le o

r 3

61

, 36

62

9.

35

4, 3

57

, 36

4, 3

67

, 37

4, 3

77

, 38

0gi

vin

g a

mo

re u

nif

orm

ly a

lign

ed

ap

pe

ara

nce

. Se

e a

lso

(aa

)

15

.n

ot

all

-wo

od

or

12

.5 o

r 5

0 c

m s

cale

s o

r 3

61

, 36

6, 3

68

*3

69

po

ssib

le fl

at

or

reb

ate

ba

ck

(h)

Nic

kel p

late

d b

rass

an

d n

icke

l sil

ver

curs

ors

are

he

avy

an

d s

hin

y (i

f th

e p

lati

ng

ha

s n

ot

wo

rn o

ff) c

om

pa

red

to

alu

min

ium

cu

rso

rs.

Wo

rn p

late

d c

urs

ors

wil

l sh

ow

an

un

de

rlyi

ng

bra

ss c

olo

ur.

Pla

ted

cu

rso

rs a

re s

ligh

tly

ma

gne

tic,

nic

kel s

ilve

r cu

rso

rs a

re n

ot.

Ba

ck la

be

l me

da

ls t

ext

Mo

de

l nu

mb

er

lab

el (

ff)

Dig

it r

egi

ste

rin

g

Ho

ok

ind

ex

for

ed

ge lo

g-

log

sca

les

Cro

ss-s

ect

ion

(ff)

Bra

nd

te

xt o

n fr

on

t (g

g)

Ba

ck la

be

l sty

le (h

h)

'Go

ld a

nd

Fir

st-c

lass

Pri

ze M

ed

als

.'

No

bo

rde

r

Soli

d b

ord

er

'Pri

ze M

ed

als

fro

m a

ll im

po

rta

nt

… e

xhib

itio

ns.

'

'Re

che

nst

ab

…'

Sma

ll b

lock

Styl

e A

Bro

ken

bo

rde

r

Top

ed

ge

Bo

tto

m e

dge

BO

X

Re

cta

ngu

lar

Fla

tte

ne

d r

ect

an

gula

r w

ith

ro

un

de

d e

dge

s

Ba

ck la

be

l aw

ard

s

Alu

min

ium

Nic

kel s

ilve

r

Wit

h 2

mm

scr

ew

s

Wit

h 1

mm

scr

ew

s

Ro

un

de

d

Squ

are

cu

t

2 e

ach

on

left

& r

igh

t e

dge

s

'St.

Lou

is 1

90

4' e

xhib

itio

n

Wit

h 2

do

me

d r

ive

ts

Styl

e B

Styl

e C

Styl

e D

'Pa

ris

19

00

' exh

ibit

ion

Ova

l

Arc

he

d s

crip

t

Wit

h 1

do

me

d &

1 fl

at

rive

t

Wit

h 2

fla

t ri

vets

Pre

sen

t (c

en

tre

riv

ete

d)

Ad

just

ab

le g

lass

Win

do

w c

orn

ers

Ten

sio

n S

pri

ng

Fra

me

ma

teri

al (

h)

Ch

ise

l in

de

xes

CU

RSO

R (e

e)

Nic

kel p

late

d b

rass

Page 7: Overview of A.W. Faber-Castell Slide Rule Dating ...Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920 - 2 - current at that time, or one of two lighter shades,

Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920

- 7 -

(aa)

Sca

le fo

rmat

s(e

e)

Cu

rso

r e

xam

ple

s

(bb

) Sl

ide

ru

le b

ack

styl

e la

be

l exa

mp

les

(cc)

Scr

ipt

M g

auge

mar

k(d

d)

Slid

e r

ule

bac

k la

be

l te

xt s

tyle

(ff)

Bo

x p

rofi

le a

nd

mo

de

l lab

el

(gg)

Bo

x b

ran

d t

ext

1. G

erm

an

2. G

erm

an

(la

rge

tex

t)

6. F

ren

ch

3. G

erm

an

(sm

allt

ext)

5. E

ngl

ish

(sm

all t

ext

)

7. E

ngl

ish

Ele

ctro

8. N

on

-En

glis

h El

ect

ro

Ad

vert

isin

g

In/c

mco

nve

rsio

n sc

ale

4. E

ngl

ish

(lar

ge t

ext

)

A. W

ith

ta

ilsB

.Wit

ho

ut

tails

Pla

in s

cale

s, d

ecim

al n

ota

tion

, han

d

pri

nte

d n

umb

ers

type

face

A, d

ispl

ace

d 1

.5

Do

ub

le li

ne

railw

ay t

rack

sca

les,

tic

ks, n

on-

de

cim

al n

ota

tio

n, t

emp

late

pri

nte

d n

um

ber

s ty

pe

face

B, a

rro

w ±

sym

bol

s

Sin

gle

lin

e ra

ilway

tra

ck s

cale

s, t

icks

, no

n-d

eci

mal

no

tati

on

, tem

pla

te p

rin

ted

nu

mb

ers

typ

efa

ce C

, arr

ow

±sy

mb

ols

Un

eq

ua

l dou

ble

line

railw

ay t

rack

sca

les,

no

tic

ks, d

ecim

al n

ota

tion

, ha

nd p

rin

ted

nu

mb

ers

typ

efa

ce A

, dis

pla

ced

1.5

Squ

are

bo

x, la

bel

wit

h n

ob

ord

er

Squ

are

bo

x, la

bel

wit

h b

roke

n b

ord

er

Fla

t b

ox

wit

h r

oun

ded

ed

ges

Ova

l bo

x, la

bel

wit

h so

lid

bo

rde

r

Nic

kelp

late

d b

rass

, ch

isel

s, 2

m

m a

dju

stin

g sc

rew

s, r

oun

ded

win

do

w, n

o s

pri

ng

Alu

min

ium

, dig

it r

egis

teri

ng w

ith

2

do

me

d r

ivet

s, r

oun

ded

win

do

w,

cen

tre

riv

ete

d sp

ring

Alu

min

ium

,ho

ok in

dex,

sq

ua

re c

ut

win

dow

, ce

ntr

e r

ive

ted

spri

ng

Arc

he

d s

cip

t'R

ech

en

stab

...'

Sma

ll b

lock

A. E

ngl

ish

(go

ld o

n b

lack

)

B. E

ngl

ish

(go

ld o

n b

lack

or

bla

ck o

n w

hite

)

C. E

ngl

ish

(re

d &

gre

ente

xt)

C. N

on

-En

glis

h (g

ree

n &

red

tex

t)

D. E

ngl

ish

(wit

h c

are

inst

ruci

ons)

D. N

on

-En

glis

h (w

ith

care

inst

ruci

ons

)

(hh

) B

ox

bac

k la

be

l sty

le e

xam

ple

s