Monroe Model K-16 Calculating Machine

The manual, full-keyboard non-printing modified stepped drum calculating machine has a metal frame painted black and a steel keyboard painted green. Eight columns of uniformly shaped black and white color-coded keys serve for data entry. At the bottom of each column is a red clearance key. Metal rods between the rows of keys are decimal markers. Three key stems are in a column to the right of the number keys. One clears the entire keyboard. The other two are set to determine whether or not the keyboard clears after each calculation (at least one of these keys looks like a replacement). A metal lever is right of the keyboard and a metal knob to the left. The operating crank on the right side rotates clockwise for addition and counterclockwise for subtraction.
The carriage behind the keyboard has a row of 16 black numeral dials for recording results, and a row of eight white numeral dials which serve as a revolution register. The revolution register, which has no carry, has black digits for addition and red ones for subtraction. Two thin metal rods between the windows for these registers carry decimal markers. The carriage shift crank is at the front of the machine. A knob for lifting the carriage is right of the result register, and a crank for zeroing dials on the carriage is on its right side. There are four rubber feet. A bell rings when the result passes through zero (as in over-division).
A mark on the front of the machine reads: MONROE. A mark on the back reads: MONROE (/) Calculating Machine Company (/) New York, U.S.A. The serial number, recorded on the bottom edge of the left side of the carriage, is 91928
J. H. McCarthy, The Business Machines and Equipment Digest, 1928, pp. 9-29 to 9-33.
Currently not on view
Object Name
calculating machine
date made
Monroe Calculating Machine Company
Physical Description
plastic (overall material)
wood (overall material)
aluminum (overall material)
steel (overall material)
overall: 19.5 cm x 46 cm x 39 cm; 7 11/16 in x 18 1/8 in x 15 11/32 in
place made
United States: New Jersey, Orange
ID Number
catalog number
maker number
accession number
Science & Mathematics
Calculating Machines
See more items in
Medicine and Science: Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Walton G. Banks, Inc.
Additional Media

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