John Wolff's Web Museum

Original-Odhner Pin-Wheel Calculator, Model 127

Original-Odhner Model 127, S/N 127-660706
Digits: 10 rotor, 13 accumulator, 8 counter
Dimensions: Body 7-1/2"W x 5-1/2"D x 5"H, overall width 14"
Weight: 11 pounds
Manufactured: Goteborg, Sweden, around 1950

This Original-Odhner Model 127 is typical of many of the pin-wheel calculators manufactured from the 1920s to the 1970s. These notes describe the essential features of its internal construction and operation.

Contents

1. Layout and construction
2. The rotor and pin-wheels
3. The carriage and registers
4. The add and carry mechanism
5. The rotor clearing mechanism
6. The back-transfer mechanism
7. Re-assembly

Resources for further information

• Christofer Noering's Swedish Typewriter Page has a history of Odhner calculators, a chart of the various models and features, and a description of the methods of calculation.

• Kevin Odhner (a relative of the inventor) has more Odhner history at his W.T.Odhner Memorial Site, with illustrations of some of the earliest models.