Tecnostyl 506 Open Triangle

This 11-1/2" transparent plastic 30°-60°-90° triangle has a triangular cutout in its interior. The long leg has a 28 cm scale divided to millimeters and numbered by ones from 0 to 28. The hypotenuse is marked with the Tecnostyl trademark (the letters T and S inside a circle) and the words: Tecnostyl (/) 506. On the back is scratched: I MOLELLA.
Tecnostyl was established in Segrate, Italy, in 1948 to sell slide rules and drafting tools. It continues to manufacture drafting tables and drawing instruments. The owner of this triangle, Isaac Giancinto Molella (1908–1982), was in the Cornell University class of 1932. The dating of other objects he donated to the Smithsonian suggests he purchased this instrument around the same time as those objects, in the 1950s, when he worked as an electrical engineer for General Electric. He was based at Electronics Park in Syracuse, N.Y., in 1953 and at radar sites in North Africa and Europe between 1954 and 1957, as a technical representative for the U.S. Air Force.
References: "Tecnostyl: Azienda," http://www.tecnostyl.it/static-28-azienda-tecnostyl-prodotti-per-ufficio.html; accession file.
Currently not on view
Object Name
date made
Physical Description
plastic (overall material)
overall: 29.4 cm x 17.5 cm x .2 cm; 11 9/16 in x 6 7/8 in x 3/32 in
place made
Italia: Lombardia, Segrate
ID Number
catalog number
accession number
Drafting, Engineering
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Squares and Triangles
Data Source
National Museum of American History, Kenneth E. Behring Center


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