Albert Nestler, Lahr in Baden / Germany                          (1930)
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                                                            VERSION (B)

S C A L E S   of  the   N E S T L E R   » K A U F M A N N «    Model 40  
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Front Side            [ inverse / RED ]                       Back Side
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( 0 ...  27 cm Ruler )

Z         X           Z = Zinsen  ( = Interest )
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T         X           T = Tage    ( = Days )           LL1   exp(0.01X)
[R]       [1/X]                                        LL2   exp(0.1X)
D         %           D = Discount = 360 / p %         LL3   exp(X)
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K         X           K = Kapital ( = Capital )

( 1:5 Ruler )

R E M A R K S :                  There are 2 Model 40 in the Collection
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Scale D is keyed to Scale T at  x = 3.6  ( = 1% for 1 Year = 360 Days )

Here the (German-) formulas & translations:

   Z = ( K * p * n )/100 ;   n = Jahre = Tage/360

(  Z = Interest; K = Capital; p = Interest Rate; n = Years; T = Days )
( ZZ = Zinseszins = Compound Interest = K * qn ,  q = 1 + 0.01 * p )

Historical Remarks ...

The slide rule came in a WOODEN BOX. It is made of mahogany with scales
on celluloid veneer.  On its back side are (worn-out) conversion tables
& formulas. To use the LL-SCALES, the slider has to be turned.  NESTLER
& "MODEL 40" are faded, but to read as BLIND PRINTS under the slider. 

The restoration took longer than expected ...
The box and the slide rule came in bad shape: The box was splittered &
the scales were dirty,  scratched and partly broken,  partly not glued.
The cursor was a  NESTLER, but not the original:  Faded 4 hairlines are
useless,  because no SquareScale for Diameter/Area-Relation exist here.
After cleaning, only the center hairline was restored.

                   Have a look at the Older Version (A)
impressum:
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© C.HAMANN         http://public.BHT-Berlin.de/hamann          04/21/09