Tacro Proportional Dividers
date: label: date made
content: ca 1940
name: label: maker
content: Tacro
notes: label: Description
content: The pointers on this German silver drawing instrument are held in place with screws, meaning that they can be adjusted and replaced. The points are 1-1/8" and 1/2" long. The front slide has scales for lines, running by ones from 1 to 10, and for circles, irregularly numbered from 6 to 36. Thumbscrews on both sides adjust the instrument along a gear and tooth mechanism (or "rack movement") on the back slide. The front slide is marked: TACRO INC. (/) GERMANY. The case is covered with black leather and lined with blue velvet. It is unlocked by pulling out a button on the right side of the case. The case is marked on the top: TACRO. It is also marked: 4130. The case is marked on the bottom: Made in Germany.
label: Description
content: Tacro is a manufacturer of drawing instruments apparently established in the 20th century. According to online auction records, it marked its products as made in West Germany from about 1950 to 1991. Thus, this object probably dates to the 1930s or 1940s. As of 2012, Tacro continues to make these proportional dividers.
label: Location
content: Currently not on view
place: label: place made
content: Germany
topic: label: Subject
content: Mathematics
label: Subject
content: Drawing Instruments
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
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content: Dividers and Compasses
creditLine: label: Credit Line
content: Gift of Ursula N. Forbes
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1986.0316.02
label: accession number
content: 1986.0316
label: catalog number
content: 1986.0316.02
objectType: label: Object Name
content: proportional dividers
label: Object Name
content: dividers
physicalDescription: label: Physical Description
content: aluminum (overall material)
label: Physical Description
content: felt (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: steel (overall material)
label: Measurements
content: overall: 2 cm x 22.8 cm x 3.8 cm; 25/32 in x 8 31/32 in x 1 1/2 in