Keuffel & Esser Deci-Lon

The Deci-Lon models 10 (10 inches) and 5 (5 inches) were manufactured in the United States form 1962 until 1972, the year K&E filed bankruptcy because the collapse of the slide rule market caused by the electronic pocket calculators surge. Considered by many experts one of the best rules manufactured in the United States and in my personal opinion also the most beautiful, it was fabricated with white Ivorite, (Acrylonitrile Butadiene Styrene (ABS) CYCOLAC™ Resin ), a smooth, white, and long wearing plastic. Scales were printed on the Ivorite, and the indicator was made with plastic hold on plastic ends with screwed metallic frames. 

K&E presented the Deci-Lon rule to scientists and engineers as the "next step in the slide rule evolution", for a low price of only $25.00 the 10 inches model ($249.00 in 2023 USD), and $12.50 the 5 inches one ($124.50 in 2023 USD) . 

The Deci-lon was replacing the 4080-4081-4181 families. With 26 scales: Ln-3, Ln-2, Ln-1, Ln-0, A [ B, T, SRT, S, C ] D, DI, K on the front face, and Sq1, Sq2, DF [ CF, L, CI, C] D, Ln 0,Ln 1,Ln 2 Ln 3 on the back face, it was produced in two sizes: 68-1100 Deci-Lon 10 (rule 13 in long, scales 10 in long) and 68-1130 Deci-Lon 5 (rule 7 in long, scales 5 in long).

Even though has not as many scales as the Pickett N-3 or the Faber Castell 2/N3, the Deci-Lon is considered a classic slide rule, a "must have" for a collector. 

Here is a link to a Deci-Lon slide rule simulator:

https://www.sliderules.org/react/k_e_decilon.html 

References:

• Soper L. Joseph. K&E Salisbury Products Division Slide Rules. The Oughtred Society. First Edition 2007 (ISBN 978-0-9791477-1-5)

• McCoys Keuffel & Esser Catalogs.  https://www.mccoys-kecatalogs.com/  

The Deci-Lon Slide Rule

       https://www.mccoys-kecatalogs.com/KECatalogs/1962/1962kecatp10.htm 

       https://www.mccoys-kecatalogs.com/KEModels/ke68-1100family.htm?fbclid=IwAR03Im3AEakTVZteS8zqHqo5QO_6cNYcqDDnAK6Ypc-MyoxCKUyJllpJTAs