Knopf Bow Compass

This German silver bow pencil has a handle engraved in a honeycomb pattern above a ring. A spiral is engraved on a disc below the ring. The width of the instrument is adjusted with a corroded metal nut between the legs. The two small screws on the front of the legs that adjust the metal and pencil points appear to be different from each other. The bow nut is marked: MADE IN USA. The nut adjusting the metal point is marked: KNOPF (/) GERMANY. The initials RW are scratched into the leg with the pencil point.
According to the donor, her husband, electrical engineer Robert H. Wieler (1923–1993), used the instrument. Jürgen Knopf began manufacturing drawing instruments and chalk in Hehlen, Germany, in 1950. He sold the company in 2010 and it was renamed PyCom. Since the object is marked as made in two different countries, it is possible that it was put together from parts of other compasses.
References: PyCom GmbH & Co. KG, "About Us,"; accession file.
Currently not on view
Object Name
bow pencil
compass, drawing
date made
mid 20th century
Physical Description
graphite (overall material)
metal (overall material)
overall: 1 cm x 4 cm x 14 cm; 13/32 in x 1 9/16 in x 5 1/2 in
place made
ID Number
catalog number
accession number
Science & Mathematics
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 Norma P. Wieler

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