Interesting mechanical calculator made by Facit in Sweeden between 1954 and 1957. A fascinating piece of history from the period shortly before computers made machines like these redundant..
This one is in good condition with no damage.
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Facit calculators work on a similar principle to the more conventional Odhner type pinwheel calculators, but their external appearance and user interface is strikingly different.
Rather than having an external moving carriage in conjunction with a fixed rotor, Facit machines reverse this arrangement and the carriage is fixed but the rotor moves. Numbers are entered into the pinwheels with numbered keys rather than by directly setting the pinwheels by hand. The user interface has advantages and disadvantages compared to the Odhner type of machine. One advantage is that number entry is quicker and less prone to error; a major disadvantage is that the input register needs to be completely cleared in order to enter a new number, making the machine unsuitable for procedures which rely on iterative modifications to the input (such as Töpler’s square root algorithm).