Pair of Keuffel & Esser 1375P-20 Chain Scales with Drafting Machine Mounts

These beveled boxwood rules are faced with white celluloid on the sloping edges. On both rules, one edge is divided to 1/32" and numbered by ones twice. The 18-3/4" rule is numbered from 0 to 36 and from 0 to 18, and the 12-3/4" rule is numbered from 0 to 24 and from 0 to 12. The other edge is divided to 1/32" and numbered by ones. The longer rule is numbered from 0 to 72, and the shorter rule is numbered from 0 to 48. As marks on the rules indicate, the first scale is "half size" and "full size," for making drawings at proportions of 1/2" and 1" to the foot. The other scale is "quarter size," for making drawings at proportions of 1/4" to the foot.

The rules are marked: PARAGON 1375P-20 K+E KEUFFEL & ESSER CO. Both ends of both rules have irregularly-shaped aluminum mounts that may be screwed to a drafting machine. A green cardboard box for the shorter rule is marked at one end: K+E PARAGON (/) DRAFT. MACH. SCALE (/) 1375P-20 12 IN. (/) MADE IN U.S.A. TRADE MARKS ®.

Keuffel & Esser was selling drafting machine scales in various configurations by 1936. The firm introduced model 1375P-20 sometime between 1943 and 1954. According to the donor, the instrument was used by her husband, the electrical engineer Robert H. Wieler (1923–1993).

References: Catalogue and Price List of Keuffel & Esser Co., 38th ed. (New York, 1936), 206–207; Catalogue and Price List of Keuffel & Esser Co., 42nd ed. (New York, 1954), 176.

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