Odhner Arithmometer

Even though the machine was very popular, the production only lasted thirty years until the factory was nationalised and closed down during the Russian revolution of 1917.

From 1892 to the middle of the 20th century, independent companies were set up all over the world to manufacture Odhner's clones and, by the 1960s, with millions sold,[1] it became one of the most successful type of mechanical calculator ever designed.

Odhner thought of his machine in 1871 while repairing a Thomas' Arithmometer (which was the only mechanical calculator in production at the time) and decided to replace its heavy, bulky Leibniz cylinder by a lighter, smaller pinwheel disk.

After Odhner's death, in 1905, his sons Alexander and Georg and son-in-law Karl Siewert continued the production[3] and about 23,000 calculators were made until the factory was nationalized during the Russian revolution and was forced to close down in 1918.

In 1950, with millions of clones manufactured, the Odhner arithmometer was one of the most popular type of mechanical calculator ever made.