Marchant Model ACR8M Calculating Machine

This full-keyboard, non-printing electric proportional gear calculating machine has a metal case painted gray and eight columns of green and white color-coded oval plastic keys. A red clearance key is at the bottom of each column. The underlying keyboard is light gray. Between banks of keys are metal rods for decimal markers.
Right of the number keys are auto divide and stop keys, subtraction and addition bars, shift keys for use in multiplication, and a reverse key. In front of these are clearance keys for the keyboard, the tab setting, and the dials. Right of these is a column of ten keys for automatic multiplication and two carriage shift keys. Above the number keys is a row of eight windows to show a number set up (the decimal markers extend from between the number keys to between these windows).
Behind this register is a movable carriage with an 16-window result register and a nine-window revolution register. Decimal markers slide above the registers on the carriage. To the left of the revolution register is a row of six buttons used in setting tabs. The motor is at the back of the machine, inside the case. Numbers are represented by the rotation of sets of gears on three shafts under the carriage.
A mark on the sides and back of the machine reads: MARCHANT. A metal tag attached to the bottom reads: ACR8M-190554
The machine has a green rubber cord and a gray plastic cover. A label on the front is from an office supply store in Baltimore, Md.
Compare to Harold T. Avery’s 1940 U.S. patents 2,216,659, 2,211,736, and 2,217,195. See 1979.3084.106 for related trade literature. The model ACR8M was manufactured from at least 1942 until 1948.
Currently not on view
Object Name
calculating machine
date made
ca 1943
Marchant Calculating Machine Company, Inc.
Physical Description
metal (overall material)
plastic (overall material)
rubber (overall material)
overall: 21 cm x 32.5 cm x 37 cm; 8 9/32 in x 12 25/32 in x 14 9/16 in
place made
United States: California, Oakland
ID Number
catalog number
accession number
maker 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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