F.420 Data Sheet MJS-p-0431

US Naval Gun Factory, Spring Slide Rule, 1939

Serial Number or Date Stamp:

Country: USA Primary construction material: pp Case included?: envelope

General Description: Specialty circular spring military slide rule

Length of 1 decade = 8 in, and overall scale length = 20 in. The largest physical dimension is 12 in.

Front Scales: D _ f [ d _ W _ G d _ W ] [ d _ W ] S _ D

Back Scales:

Notes: Cardboard Spring Design slide rule made for naval guns; plastic cursor; WWB = wrought wire, brass; AHY = Alloy, High-Yield (Chrom Nickel alloy) Jan. 1939; U.S. Naval Gun Factory, Washington, D.C.

References: https://chrs.org/naval-gun-factory-pc/

Date Acquired: 06/15/2026