Comptometer Model F

This full-keyboard non-printing adding machine has a copper-colored steel case. The keys are in ten columns, colored according to the place value of the digit entered. Complementary digits are indicated on them. The keys are alternately concave (odd digits) and flat (even digits). At the front are subtraction levers and numbered decimal markers. In front of these are eleven windows, covered with clear plastic, which reveal the result on the number wheels. A zeroing lever is on the right side. This is the last of the Comptometers to be designed by Dorr E. Felt. After this, the firm of Felt & Tarrant relied on the work of other inventors.
The machine has serial number 130780, which is indicated to the left of the keyboard. A metal plate screwed to the top of the machine in back of the keyboard is marked: TRADE COMPTOMETER MARK (/) PAT’D [. . .] (/) Felt & Tarrant Mfg. Co. (/) CHICAGO. The last patent date listed on the plate is: SEP.15.14
A Model F Comptometer with serial number 100,346 was produced in May, 1915, hence this machine is somewhat later. The model H succeeded the model F in 1920.
This machine was a gift of John T. Cheney of Washington, D.C.
Felt & Tarrant, Accession Journal 1991.3107.06
Currently not on view
Object Name
adding machine
date made
Felt & Tarrant Manufacturing Company
Physical Description
wood (overall material)
steel (overall material)
plastic (overall material)
overall: 14.3 cm x 27.5 cm x 36 cm; 5 5/8 in x 10 13/16 in x 14 3/16 in
place made
United States: Illinois, Chicago
ID Number
maker number
catalog number
accession number
Science & Mathematics
Adding Machines
See more items in
Medicine and Science: Mathematics
Adding Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of John T. Cheney
Additional Media

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