Uploaded December 2020 | Updated September 2026, 1 hour ago

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The Thales model A is an early mechanical calculator that uses a pinwheel mechanism of the standard Odhner design. In this video I demonstrate this mechanism.

In my other video I show how the machine is used normally.
youtu.be/-UbS4MqyndE

For more information on this machine and other mechanical calculators in my collection, please visit my website:
jaapsch.net/mechcalc

0:00 Introduction
0:24 Carriage
2:22 Clearing mechanism
2:59 Crank cycle
5:30 Input pins
6:03 Carry mechanism
7:46 Counter mechanism
8:08 Latch
9:45 Outro