Keuffel & Esser 4083-5 Log Log Vector Duplex Slide Rule

This 20-inch mahogany duplex slide rule is coated with white celluloid and held together with metal end pieces. On one side, the base has LL02, LL03, DF, D, LL3, and LL2 scales, with CF, CIF, CI, and C scales on the slide. The right end of the slide is marked in red: © (/) K + E. On the other side, the base has Sh1, Sh2, Th, A, D, DI, LL01, and LL1 scales, with B, T, SRT, and S scales on the slide. The first three scales are hypobolic scales. The trigonometric scales are divided into degrees and into decimals. The left end of the slide has a serial number: 640023. The left ends of both parts of the base are marked: 023. A glass indicator has plastic edges and metal screws. Compare to MA.318481

The top edge of the rule is marked: PATS. PEND. MADE IN U.S.A. 4083-5 LOG LOG DUPLEX VECTOR ® COPYRIGHT 1947 BY KEUFFEL & ESSER CO. PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. See 2007.0181.01 for a description of these patents. There is a green leather case with metal inlays on the holder for the flap. One of the inlays is marked: PAT. 2,000,337. The flap is marked: K + E. Adolf W. Keuffel applied to patent his method for securing a slide rule case on November 1, 1932, and received the patent on May 7, 1935.

Keuffel & Esser of New York used this set of scales on this model number from 1955 to 1962. The serial number is consistent with a date later in this time frame. The rule sold with the leather case for $56.50 in the 1950s.

References: Adolf W. Keuffel, "Slide Rule Case" (U.S. Patent 2,000,337 issued May 7, 1935); K + E Catalog, 42nd ed. (New York: Keuffel & Esser Co., 1954), 280–281; Keuffel & Esser Co., "Price List Applying to the 42nd Edition Catalog" (New York, June 1, 1956), 43; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4083-3 Family of Slide Rules," http://www.mccoys-kecatalogs.com/KEModels/ke4083-3family.htm; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg.

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