Electromechanical calculating machines from the 1960's
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Rotary calculators
Badenia VA-17
Badenia VARE-17
Bohn Contex 55
Cellatron R44SM
Diehl DSR-18
Diehl VSR-18
Facit CA1-13
Friden SBT
Friden SVE
Friden SRW
Friden SRQ
Friden RSR
Hamann 505
Madas 20 BTG
Marchant ABL
Marchant SKA DeciMagic
Marchant Tenkeymatic
Monroe IQ-213
Olympia RA-16

Soemtron 214

Printing calculators



Other calculating devices

References and links




Rotary calculators

These mechanical calculators do not print: instead the results are displayed on a series of rotating number dials. Their main advantages compared to printing calculators are their greater speed, particularly in division, greater capacity and greater flexibility for complicated calculations.

Most of the internal mechanisms are evolutions of machines developed in the 1930's and 40's. The last of the rotary calculators attempted to incorporate advanced features such as shortcut multiplication, automatic decimal point placement and mechanical memory. However, as the cost of electronic calculators dropped, even the most advanced mechanical models were not competitive, and the rotary calculator was gone from the market by 1970.