Sundstrand Adding Machine - Underwood Sundstrand
The Sundstrand Adding Machine circa 1920
Rockford, Illinois U.S.A source: ebay and various (including PierceFuller)
David Sundstrand, in 1911, invented an adding machine that was the very first to use the '3x3 above zero' key arrangement, which became widely adopted and to this day is standard on calculator and computer keypads around the world.
Sundstrand 10 key keypad closeup circa 1914
The Sundstrand was the first to use this 10-key arrangement, which is ubiquitous today.
The red keys are: 'Non-Print', 'Error', 'Repeat', 'Lock', 'Non-Add', 'Total'.
Ads for The Sundstrand Adding Machine 1923
This machine was the first in the U.S. to offer 'Direct Subtraction'
Saturday Evening Post (source: AdsOfThePast with permission)
David and Oscar Sundstrand
In 1927, Oscar (the younger brother) and David Sundstrand sold the rights to market and distribute the Sundstrand machine to Underwood-Elliot Fisher Co., a typewriter and office equipment manufacturer, and the machines thereafter bore the mark of Underwood Sundstrand. David died in 1930, but Oscar joined Underwood and continued developing the Sundstrand adding machine until 1949. He later joined Victor and helped design their successful line of printing calculators in the 1950s.
Underwood Sundstrand Model 8100 Serial Number 350119
Circa 1940? (source L. Simpson)
Underwood Sundstrand Adding Machine circa 1948?
Underwood Sundstrand Adding Machine Model 9120 circa 1955?
Instruction Manual Front Cover circa 1920
Underwood Sundstrand Model List (source
, Maurepas, France (c) 1997)
Ad for The Sundstrand Adding Machine Showing 3 models
The Special Junior, Automatic Cross Tabulator, the Marvel Model,Saturday Evening Post 1925
Booth Display Period Photo circa 1920
Winter and Pond. Photographs, 1893-1943. ASL-PCA-87
This page has a photo of the Sundstrand and competitors from the era: www.novosite.nl