The 10-inch "Universal Mannheim" was Post's most important closed-body slide rule from 1931 until the end of the slide rule business. From 1931 to c1950 the top surface was 28 mm wide (Hemmi 50). After 1950 it was 34 mm wide (Hemmi 50W).
|1955 Frederick Post General Catalog, Pages 64-65
Top edge (slanted): 0-10 inches
Lower slide is from a Post 1452W with date code "PE" (May 1965). Note that the smallest labelled division on the S scale is 40'; Hemmi reverted to "Mannheim" sine scales about 1955. Click here for a discussion of Hemmi trig scales.