Antique K&E Keuffel Esser 4092-3 Log Log Duplex Slide Rule Leather Case For Sale

Antique Keuffel & Esser Co. K&E Model 4092-3 Log Log Duplex slide rule, made in the USA, complete with its original fitted brown leather carrying case.

This is K&E's classic 10-inch double-sided engineering/calculating rule, constructed of mahogany with cream-colored celluloid scale surfaces and metal end fittings. It retains its glass cursor/indicator with green metal fittings.

Marked:

KEUFFEL & ESSER CO. N.Y.
PAT. JUNE 5 '00 DEC. 22 '08 APRIL 1 '24
MADE IN U.S.A.
Model 4092-3
Serial number 149082

K&E introduced the 4092-3 in 1922 and continued producing the model through the 1930s; the April 1924 patent marking and serial number place this example in the earlier period of the model's production.

The rule includes numerous logarithmic and trigonometric scales including LL, A, B, S, T, C and related scales used for engineering and scientific calculations before electronic calculators.

Approximately 13 in / 33 cm overall length including the end fittings; nominal 10-inch calculating scale. Original leather case approximately 13¼ in / 33.7 cm long.

Very good vintage condition. The celluloid scale surfaces remain remarkably clean and legible with age-related toning and scattered minor marks. Metal fittings show attractive oxidation/patina, particularly the green-finished cursor hardware. Glass cursor appears intact. Slide and cursor are present and movable. Original leather case remains intact with substantial age-related surface wear, darkening, scuffs, scratches and finish loss. Closure hardware is present. Please review photographs closely.

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