Sundstrand CS

Sundstrand CS

**Sundstrand CS**

The Sundstrand CS is a mechanical 10-key calculating and adding machine manufactured around 1920 by the Sundstrand Adding Machine Company in Rockford, Illinois, USA. The company later became known as Underwood-Sundstrand following corporate consolidations in the late 1920s.

The machine is capable of handling and listing numbers and totals of up to nine digits. It was designed by Gustaf David Sundstrand and pioneered the 3 × 3-over-0 numeric keypad layout, with the numbers 1–9 arranged in a 3 × 3 block and the 0 key positioned below. This design became the foundation for modern numeric keypads and computer keyboards.

The machine operates as an adding and listing machine, printing entries and totals onto a paper roll using a ribbon-based printing mechanism. The CS model is equipped with a 12.5 cm-wide carriage.

The machine has a European distributor's label on the front panel. Aktiebolaget Hadar Schmidt was a Swedish general agent and distributor based in Stockholm, with branches in Göteborg and Malmö. The company imported and sold mechanical adding and calculating machines, most notably Sundstrand (later Underwood-Sundstrand) 10-key adding machines and bookkeeping equipment, in Sweden during the early to mid-20th century, particularly in the 1920s and 1930s.

Year of manufacture: 1920s

Serial №: 26585