Keuffel & Esser K&E 20-inch "Mystery" Slide Rule w/ side K scale- Serial #924660

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Here is a rare Keuffel & Esser K&E 20-inch "Mystery" slide rule w/ side K scale and S, A, T scales on the reverse of the slider. Serial #924660. Considered a mystery because no one knows for certain who K&E made this particular type of slide rule for or for what purpose.

The slide rule is made of mahogany with celluloid plastic surface and measures approximately 20 1/2 inches long by 1 1/8 inches wide (top face) and 1 3/8 inches wide (bottom face).

The sliderule is in good condition, showing normal signs of age. It has a bump and small crack in the celluloid on one corner and a small chip above the side serial number. The case is in fair condition, showing normal signs of age and storage, including scratches, creases, dirt, bumps, scrapes, etc. It is also missing the flap. Please see pictures.

The scales are:

A [B, CI, C] D, L

and

[S, A, T]

and

K (on the side)

(You can see the actual scales by clicking on the pictures.)

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Please check my other listings for other items, including more slide rules. Please feel free to email with any questions. Thanks for looking! baja_ron

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