Check out the latest addition to my ⁨⁩ ⁨⁩ collection! This is a Marchant "Silent Speed" 8D from 1940, a fast electromechanical analog calculator that can even infinite loop if you divide by zero. I'll be refurbishing it this weekend to make it fully functional.

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Anyone interested in mechanical engineering should definitely check out the *analog* carry mechanism in these Marchant calculators that relies on planetary gears. These Marchants are arguably the high water mark for electromechanical calculator engineering.

From John Wolff's museum:
"The Marchant "Silent Speed" and its descendants use a complex and unusual continuous-drive mechanism based on proportional and differential gearing. Every column incorporates a ten-speed gearbox with three drive shafts and five selectors. The accumulator tens-carry mechanism is contained within the carriage, using a differential gearing mechanism with two planetary gearsets per digit."

johnwolff.id.au/calculators/Ma

See also Jaap's pages:
jaapsch.net/mechcalc/marchant.

@kyle

@EdS I relied on John Wolff's documentation when I was attempting to repair a previous Silent Speed. Incredibly complex machines. The official service manual just had drawings and it was handy to see high-quality pictures of the mechanisms.

@EdS Cf. Neal Stephenson's "rod logic" from The Diamond Age.

@kyle

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