STW-10 is an electromechanical calculator produced by the American company Friden in 1949. It’s a slightly modified version of the ST-10 calculator, which was marketed throughout World War II, and which saw the participation of Carl Friden, founder of the company called after his name, in its design planning. Thanks to its solidity, reliability and (for the time) convenience, STW-10 met with large success, especially with insurance companies, and its production went on until 1966.
Insights
Compared to modern calculators, STW-10 is equipped with two keypads: one for inputting the values to be added or subtracted, and one for inputting the multiplicand in multiplication operations. The first keypad, in particular, has a set of keys from 1 to 9 - placed in 10 columns - for each figure of the value to be entered. To enter the value 103, for example, it is necessary to press on key 1 of the third column set, and on key 3 of the first column set.
The “Friden Inc.” was an American firm that manufactured typewriters and electromechanical calculators, founded in 1934 by Carl Friden. In 1957 it acquired the “Commercial Control Corporation” and it expanded into the production of transistor calculators, such as the model EC-130 (1963) which had a 13-figures capacity. The company continued to operate and was known as “Friden” until 1974 even if it had been purchased by Singer Corporation. In the 1970s, the company was not able to compete with new Japanese pocket calculator technologies, and it ended its production and research activities.
Bibliography
https://www.oldcalculatormuseum.com/fridenstw.html
http://rechner-lexikon.de/it/artikel/Friden_STW_10
