Bruning 2420 Slide Rule

Bruning 2420 Slide Rule

<< >>
Usage conditions apply
This one-sided, ten-inch slide rule is made from white molded plastic. The indicator has a metal frame. The base of the rule has an A scale at the top and D and K scales at the bottom. The slide has B, CI and C scales on one side and S, L, and T scales on the other. The edges of the rule are beveled with a twenty-five centimeter scale along the bottom edge, divided to millimeters. The top edge has a twelve-inch scale, divided to 1/16".
The back of the rule has tables of equivalents to be used from converting between metric and common measures, as well as a few common formulae. Four metal screws hold the instrument together.
The rule fits in a sturdy paper case covered with what appears to be black plastic. A leather flap at one end snaps to close the case
A paper "Instruction Manual for 10-Inch Pocket Slide Rule A-B-CI-C-D-K-S-L. and T Scales" comes with the instrument. It is copyrighted 1943.
According to the donor, the instrument was given to him by an uncle, Frank Vignola, who worked at a New York City industrial machine shop during World War II. The shop made landing gear struts for carrier based aircraft.
Compare 1998.0032.09.
Currently not on view
Object Name
calculating rule
slide rule
Calculating Rule
date made
ca 1945
Charles Bruning Company
place made
United States: Illinois, Chicago
Physical Description
plastic (slide, base material)
paper (case, instructions material)
metal (screws, indicator frame material)
rule in case: 2 cm x 29.4 cm x 5 cm; 25/32 in x 11 9/16 in x 1 31/32 in
instructions unfolded:.3 cm x 14.5 cm x 22.5 cm; 1/8 in x 5 23/32 in x 8 27/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Daniel Mauro
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object