Marchant Model 8M Calculating Machine

This full-keyboard, non-printing electric proportional gear calculating machine has a metal case painted black . The eight columns of green and white color-coded plastic keys have a maroon clearance key at the bottom of each column. The underlying keyboard is painted gold. 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 dials. Right of these is a column of 10 keys for automatic multiplication and two carriage shift keys. Left of the number keys is an on-off switch. 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 the entry register is a movable carriage with an 18-window result register and an eight-window revolution register. Sliding decimal markers for the registers are on the carriage. Pushing down a lever on the right side of the carriage allows manual movement of the carriage. Numbers are represented on this machine by the rotation of sets of gears on three shafts under the carriage.

Marks on the right and left sides and on the back read: MARCHANT. A mark on the bottom reads: 8-M-112591. A mark on the back at the bottom reads: MADE IN U.S.A. A mark on the motor reads: GENERAL GE ELECTRIC (/) UNIVERSAL MOTOR.

Compare to Harold T. Avery’s 1940 U.S. patents 2,216,659, 2,211,736, and 2,217,195.

The Marchant Model M was introduced in 1935. The model 8M sold from 1935 until 1941

Reference:

American Office Machines Research Service vol. 3, 1938, section 4.3, p. 14–16, as well as section 4.13 under “Marchant.”

Currently not on view