The Marchant ACT-10M mechanical calculator

The Marchant ACT-10M was made between 1942 and 1948, though mine is likely to be one of the later ones. It uses a proportional gear mechanism which was the fastest general calculation method until electronics came along. In this video I show what all its buttons and switches do. Other related videos: The STOP button of the Marchant ACT-10M calculator:    • The STOP button of the Marchant ACT-10M ca...   Marchant ACT-10M doing division in slow motion:    • Marchant ACT-10M doing division in slow mo...   The Marchant XL:    • The Marchant XL Calculator   For more information about this machine and other calculators in my collection, please visit my site: https://www.jaapsch.net/mechcalc/ 0:00 Introduction 0:40 Addition 1:09 Subtraction 1:40 Clearing 2:22 Multiplication 4:26 Tabulation 6:05 Division 8:25 Stopping division 9:07 Reverse button 10:01 Outro