Monroe Model CSAE-10 Calculating Machine

This full-keyboard, electric non-printing modified stepped drum calculating machine has a dark gray steel frame, a light gray keyboard and carriage, and ten columns of oblong plastic keys in two shades of gray. At the bottom of each column is a key for clearing it. Between the columns of keys and under the keyboard are metal rods, painted red on one side and the same gray as the keyboard on the other. They turn to serve as decimal markers.

To the right of the number keys are subtraction and addition bars, two carriage shift keys, and a multiplier key. Below these are two buttons, one of which is depressed when entries are repeated and the other depressed for non-repeating entries. This section also has a multiply/divide lever. Below these are three other function keys and a gray clear-keyboard key. Beneath the number keys are five additional function keys.

In back of the keyboard is a carriage with ten dials to show a number set up for multiplication, 20 dials to show the result, and a row of ten dials that serves as a revolution counter. Sliding decimal markers are provided. A two-pronged gray electrical cord attaches to the back.

An incomplete mark on the left side reads: omatic. A mark on the front reads: Classmate. Another mark there reads: li. A paper sticker glued to the bottom of the machine reads: MONROE INTERNATIONAL CORPORATION [/] A DIVISION OF LITTON INDUSTRIES [/] ORANGE, NEW JERSEY. A list of 28 patents on this sticker ranges from number 2,473,422 (1949) to D-192,457 (1962). A metal tag attached to the bottom of the machine reads: MODEL CSAE-10 [/] SERIAL B066597. Scratched on the frame at the back are the initials: EHS.

This is a relatively late mechanical calculating machine, produced by Monroe after it became a division of Litton Industries in 1958. The rough date is based on the patent date.

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