Keuffel & Esser 4053 Polyphase Mannheim

This rule was fabricated in the United States from 1909 to 1967. It was available in three different sizes: 8 inches long (4053-2), 10 inches long (4053-3), and 20 inches long (4053-5). It was fabricated from wood covered with celluloid, where 9 standard scales were engraved:A-B, C-D, CI, S, T and L. At its back, this rule had the instructions to perform a wide range of units conversions.

This rule never had changes in the scales included or their position. The only change was in the type of cursor included. The oldest was the frame-less cursor, included with the models fabricated between 1915 - 1936, the framed cursor was used after 1936. The original costs of the 4053 models by 1915 were $5.00 (~$136.00 in 2021 USD)  for 8 and 10 inches sizes, and $14.00 (~$380.00 in 2012 UAD) for the 22 inches size. By 1935 the selling cost was $7.10 (~$142.00 in 2021 USD) and 17.50 (~$351.00 in 2020 USD), respectively.

As it can be seen in the above picture, there were adds for these rules like the magnifier lenses attachable to the cursors to ease the reading of the scales and improve the precision in the calculations. There was also used a more "primitive" cursor, all metallic, in models fabricated between 1900-1915. You can see below a specimen form those years, with its magnifying to facilitate the scales reading.

All these rules had at the back a useful reference units equivalences and of how to perform unit transformations using scales C-D. Following these instructions was simple to transform inches into cm, square miles in square Km, or gallons in liters.   

Between 1955 and 1959 K&E produced a 5" long plastic version, labeled 4153-1, and a 12" plastic laminated version with the same label 4053-3, with an improved cursor. The original selling price of these models were  between $13.50 - $16.50 ($138.00-$169.00 in 2021 USD), depending on the case quality, for the 12 inches size, and between $27.00 - $33.00 ($276.00-$338.00 in 2021 USD), for the 20 inches size.

With these nine scales, an skillful slide rule user is able to perform the next Math operations, with two-three decimals precision:

SlideRulePractice-1.pdf

To see in detail the operation of these rules, and the some application problems, you can see the K&E 4053 User Manual:

M44_KE_ThePolyphaseSlideRule_N4053_1944.pdf

References:

This website is the most extensive digitla file of Keuffel and Esser product catalogs and price lists (prices  shown here were taken from these lists)  from 1881 until 1972. You can find also user manuals for many slide rule models, as well as other interesting brochures and materials.


This website gives a good overview of models, and other interesting information and links