Brown & Sharpe 510 Draftsman's Protractor
date: label: date made
content: ca 1925
name: label: maker
content: Brown & Sharpe Manufacturing Company
notes: label: Description
content: See also ID number 1977.0460.01. After the inventor of this draftsman's protractor, Alton J. Shaw, left Darling, Brown & Sharpe of Providence, R.I., Samuel Darling patented a vernier scale that was a fraction of the size of a standard vernier scale. Darling then claimed to apply his vernier to the draftsman's protractor, replacing the original patent date in the maker's mark with the December 2, 1890, date of this patent. See, for example, the illustration in Brown & Sharpe's 1899 <i>Catalogue No. 101 and Price Lists</i>. This vernier read to only five minutes of accuracy, while Shaw's earlier vernier read to one minute of accuracy. Darling argued, however, that the coarser scale was easier to read and sufficed for most situations that arose in engineering drawing.
label: Description
content: In any event, the draftsman's protractor continued to sell steadily into the 20th century. Advertisements extolled the instrument's versatility, including its ability to function as a drawing triangle and as an extension of a T-square. The original patent date reappeared on the instrument in 1902 and 1904 but disappeared again by 1916, by which time Brown & Sharpe also changed the protractor's catalog number from 530 to 510. Other dealers, including Keuffel & Esser, W. & L. E. Gurley, and L. S. Starrett, also sold the draftsmen's protractor.
label: Description
content: The chief difference between this example of the instrument and ID number 1977.0460.01 is the reduced precision of the vernier, which is even marked: FIVE MINUTES. This protractor has 40 unmarked divisions, instead of 30. The signature is: 510; BROWN & SHARPE MFG. CO. (/) PROVIDENCE. R.I. U.S.A. The handle also bears the Brown & Sharpe logo of two rectangles at right angles to one another, with the letters B∙S above the horizontal rectangle and the words TRADE MARK below the horizontal rectangle. Of surviving 20th-century Brown & Sharpe catalogs, this protractor most closely resembles the illustration printed in 1925. The extending arm of the protractor is rusting.
label: Description
content: The protractor is stored in a blue paper box covered with the company logo and the words BROWN & SHARPE. A label on one end of the lid reads: 510; ORDER BY NUMBER 599-510 (/) BROWN & SHARPE DRAFTSMEN'S PROTRACTOR (/) MADE IN U.S.A. A label on the other end of the lid reads: POST (/) 0585 (/) THE FREDERICK POST CO. CHICAGO. Post retailed scientific and drawing instruments in the 20th century. An undated sheet with tables of angles for dividing circles and for tapers per foot is in the box.
label: Description
content: References: Samuel Darling, "Vernier-Scale" (U.S. Patent 442,020 issued December 2, 1890); Kenneth L. Cope, intro., <I>A Brown & Sharpe Catalogue Collection, 1868 to 1899</I> (Mendham, N.J.: The Astragal Press, 1997); Brown & Sharpe Mfg. Co., <I>Catalogue</I> (Providence, R.I., 1902), 372; Brown & Sharpe Mfg. Co., <I>Catalogue No. 138</I> (Providence, R.I., 1925), 504–505.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
label: Subject
content: Protractor
label: Subject
content: Drafting, Engineering
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Protractors
creditLine: label: Credit Line
content: Gift of Mrs. Alice W. Smith
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1990.0317.02
label: accession number
content: 1990.0317
label: catalog number
content: 1990.0317.02
objectType: label: Object Name
content: protractor
physicalDescription: label: Physical Description
content: paper (overall material)
label: Physical Description
content: sheet steel (overall material)
label: Measurements
content: overall: 1.5 cm x 27.5 cm x 16.8 cm; 19/32 in x 10 13/16 in x 6 5/8 in