Hairspring Compass

The handle on this metal instrument is connected to the point and can be pulled out of the cylinder that is the compass's main leg. The other leg is screwed to the cylinder with a metal slat. A screw goes through this leg and can be loosened or tightened to adjust the radius of a circle drawn with the compass. A second screw adjusts the tube that holds a pencil point. Draftsmen used the hairspring compass to precisely draw small circles.
Keuffel & Esser, an American maker and dealer of slide rules and drawing instruments, donated this object to the Smithsonian in 1971. Part of a paper tag received with the object has been lost, but the remaining portion suggests this instrument may have come from Leipzig, Germany. None of the compasses offered in K&E catalogs in 1909, 1921, or 1936 resemble this instrument.
Currently not on view
Object Name
compass, drawing
date made
ca 1900
Keuffel & Esser Co.
Physical Description
metal (overall material)
overall: 1.1 cm x 12.1 cm x 2.3 cm; 7/16 in x 4 3/4 in x 29/32 in
ID Number
accession number
catalog number
Science & Mathematics
Drafting, Engineering
Drawing Instruments
Dividers and Compasses
See more items in
Medicine and Science: Mathematics
Dividers and Compasses
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Keuffel & Esser Company

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