Hemmi Simplex Slide Rule Retailed by Post (1446)

Hemmi Simplex Slide Rule Retailed by Post (1446)

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Usage conditions apply
Hemmi, a Japanese slide rule firm established in 1895, became notable after it began in 1912 to apply celluloid to bamboo, resulting in rules that did not shrink or expand like wooden rules. Hemmi also made rules for export, and it became the sole supplier of linear slide rules to the Frederick W. Post Company of Chicago by 1932. Post sold model 1446 between 1931 and 1949 for $1.50. The donor reported that he purchased this example in 1936 while studying at Colgate University. This date is consistent with the company logo on the case, which was in use in the 1930s, and with the lack of reference on the instrument to "Occupied Japan," as Hemmi rules were marked from 1946 to 1950. Hemmi products were not available in the United States during World War II.
This one-sided bamboo rule is coated with white celluloid only on the front. There are A and D scales on the base. The D scale is marked at each end: Quot (/) +1; Prod (/) -1. The slide has B and C scales on one side and S, L, and T scales on the other side. The indicator is glass in a metal frame. The rule's backing is clear and silver celluloid. It contains a chart with fractions converted to decimal numbers, powers of П, relationships between scales C and D, and weights of metals.
The center top of the base is marked in red: THE FREDERICK POST CO. NO. 1446. The center bottom of the base is marked in black: "SUN" (between two drawings of the sun); HEMMI; MADE IN JAPAN. The edge of the indicator is also engraved: SUN (between two drawings of the sun) HEMMI.
The rule is stored in a rectangular black Fabrikoid case which is opened by removing the right end. This end is marked in white: POSTS (/) 1446. The back of the case is marked: MADE IN JAPAN. The rule came with a stapled leaflet of instructions, 1982.0386.03.
References: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 79–82; International Slide Rule Museum, "Slide Rule Dates and Time-Lines," http://sliderulemuseum.com/SR_Dates.htm; Posts Dependable Drawing Materials, 18th ed. (Chicago: The Frederick Post Company, 1936), 174. Price lists for this catalog dated August 1937 and May 1940 show model 1446 on pages 11–12 and 27–28, respectively.
Currently not on view
Object Name
slide rule
date made
Frederick Post Co.
place sold
United States: Illinois, Chicago
place made
Japan: Japan
Physical Description
bamboo (overall material)
celluloid (laminate material)
glass (cursor material)
fabricoid (case material)
paper (part material)
overall: 4 cm x 29.2 cm x 3.9 cm; 1 9/16 in x 11 1/2 in x 1 17/32 in
ID Number
accession number
catalog number
Credit Line
Gift of John A. Betcher
General Calculation
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History
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I bought this model on an antique shop in Roanoke, VA, last week for less than $15. Our algebra and calculus teacher from high school, I graduated in 1984, made us learn to use these and sometime required us to check our "slide rule calculators" with one of these. Alas, I have forgotten how to use it but had to have it when I saw it. RIP, Ella Jean!
I recently acquired one at an auction. I learned how to use one while in High School in the early 70's. It is a very good addition to the one I have from then but smaller.
My father had this exact model slide shown here. He was a radio mechanic in the Army Air Corp during WWII primarily stationed at Laughlin Air Base. After discharge from the Army Air Corp after the war he worked as a machinist for a while in Dallas. I do not know whether he used this during the time he was a radio mechanic or a machinist. I just remember it being in his chest of drawers. Once he took it out and explained to me that it was a slide rule. I would rummage through his drawers from time to time looking at all the unusual and neat things he collected and saved. I always admired this slide rule. He died in 1991. I now have his slide rule. It brings me great joy knowing I have it. I'm now 74 and never learned how to use it. I took it our of my chest of drawers today and my plan is to teach myself how to use it. I'm thrilled. Thanks for letting me share a memory.

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