Open Triangle

This 12" 30°-60°-90° triangle with an open interior is made of two different woods, with a section of darker wood set between two sections of lighter wood. Each corner is reinforced with horizontal splines made from the lighter wood: two in the right angle, and three in the other two angles. The back of the object has a sticker marked: 838. Compare to 1977.1101.0087, MA.335329, and MA.335330.
Neither Keuffel & Esser nor the Eugene Dietzgen Company advertised triangles like this one. James W. Queen of Philadelphia offered two-toned triangles, of walnut or mahogany with a maple or ebony inlay, but they did not have the splines. The previous owner of this instrument collected more than 1,200 hand tools and machine tools and displayed them at his family's building company in Baltimore, Md. This object was item number 838 in his collection.
Currently not on view
date made
ca 1900
Physical Description
wood (overall material)
overall: 30 cm x 17.7 cm x .3 cm; 11 13/16 in x 6 31/32 in x 1/8 in
ID Number
catalog number
accession number
Credit Line
The John R. Gerwig, Jr., Collection
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Squares and Triangles
Data Source
National Museum of American History


Add a comment about this object