Dotting Instrument

Description
This 2-1/4" German silver drawing instrument consists of a teardrop-shaped plate to which is attached a mechanism that links a serrated wheel to a bar that holds a pen point. When the wheel is rolled along the edge of a T-square or straight edge, the pen point bounces up and down to make a line of dots. Draftsmen would then retrace and fill in the line, if desired, while they were finishing an engineering drawing.
Underneath the uniformly serrated German silver wheel is a brass wheel with a pattern of three and one serrations. This wheel is marked: 6. It could be interchanged with one of four other brass wheels to change the dotting pattern. The instrument originally had six pattern wheels, but the one numbered with a "2" is missing.
The back of the plate is marked: 1050. The instrument is in a rectangular wooden case covered with brown and black leather and lined with dark blue velvet and satin. The Eugene Dietzgen Co. of Chicago and Technical Supply Company (TSC) of Scranton, Pa., sold a similar dotting instrument in the early 20th century for prices ranging from $4.20 to $5.15. According to the 1904 Dietzgen catalog, E. O. Richter of Germany made the instrument sold at that time. Unlike the Dietzgen and TSC instruments, this example has a screw that allows the pen point to be removed from the bar. Compare to 1982.0147.01.
References: Catalog of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 88; Catalog of Eugene Dietzgen Co., 12th ed. (Chicago, 1926), 84; Technical Supply Company, Complete Catalog and Supply List, 5th ed. (Scranton, Pa., 1912), 91.
Location
Currently not on view
Object Name
pen, dotting
date made
early 20th century
Physical Description
german silver (overall material)
brass (overall material)
wood (overall material)
leather (overall material)
cloth (overall material)
Measurements
overall: 1.7 cm x 9.7 cm x 6.8 cm; 21/32 in x 3 13/16 in x 2 11/16 in
ID Number
1987.0788.02
accession number
1987.0788
catalog number
1987.0788.02
subject
Pens and Pencils
Science & Mathematics
Mathematics
Drafting, Engineering
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Pens and Pencils
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Howard I. Chappelle
Additional Media

Visitor Comments

Add a comment about this object

Submit a comment or ask a question about this object using the form below. Submissions are moderated and may receive a curator response. Please note that we cannot evaluate or appraise your personal artifacts. For other questions or general inquiries please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Image CAPTCHA
Enter the characters shown in the image.