Keuffel & Esser Mannheim 4161-3 & 4161-1

The Mannheim 4161 family was manufactured in the United States from 1952 to 1972. It was fabricated with Ivorite, (Acrylonitrile Butadiene Styrene (ABS) CYCOLAC™ Resin ), a smooth, white, and long wearing plastic. Scales were printed on the Ivorite, and the single glass metallic frame indicator was screwed to plastic ends . It was an advanced version of the 4053 model, with the main difference that the 4161 had the folded scales DF-CF in the position the A-B scales had on the 4053. The A-B scales were relocated: A at the bottom of the front face, and B at the back of the slider, but labeled C. In 1967 the 4161-3 and the 4161-1 were re-named Jet Math Group, and the model numbers changed to 68-1576 and 68-1581 respectively (1).

The scales on the 4161-3 model were: inches- K DF [CF L CI C] D A -centimetres on the front face, and [T ST S C] on the back of the slider. There were units conversion tables on the back side of the rule.

The original prices for these models in 1962 were: $ 11.00 for the 10" 68-1576 ($109.58  in 2023 USD), and $7.50 for the 5" 68-1581 ($74.71 in 2023 USD)

With these scales, an skilled user can solve the next problems with a precision of 2-3 decimals:

SlideRulePractice-1.pdf

Next is the 4161 User Manual 

M21_KE_4161_Manual_1952.pdf

Click on the next links to see professional panoramic pictures of the 4161 model. 

References:

(1). McCoy, Clark: K&E 1962 Catalog, The Modern Polyphase Group. http://www.mccoys-kecatalogs.com/KECatalogs/1962/1962kecatp21.htm 


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