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Design of mechanical calculators

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woodchips:
Just pulled one of my old mechanical calculators from the shelf to get it running, show to those who have never seen or heard one.

It is a Marchant Figurematic, only because I bought it many years ago less its covers, so already open to inspection. Needed some work to free it off so the motor shaft would rotate and the contacts open to stop the motor. Then I tried putting power on to see if it would run, no. Showers of sparks from the commutator and small cloud of blue smoke. Did try to sort out why but in the end removed the motor and on dismantling the commutator was black from backed on oil. Will need to get in the lathe to clean it up.

But, my question is, after just admiring it whilst drinking a tea, is could you design the calculator using CAD.

For example there are many oddly shaped pieces of metal, but they also have odd lumps and bumps that push other pieces of metal. Also many odd pins that similarly push against or prevent movement of other pices of metal. Then there a springs everywhere, seemingly fixed at any convenient point.

My question is, does CAD allow you to design a particular piece of metal from a key that also understands that there are lumps and pins etc that are interlocks to stop that key being pressed if some other key or operation is in progress. Do you see what I am trying to explain?

The next question is, can you put the contents of the calculator into the CAD program, together with all the interlock and accompanying operations and the CAD package will tell you how the calculator works?

The biggest problem with fixing a calculator is to simply know what each piece of metal does, and when it does it. It is virtually impossible to understand the complexity of the calculator.

Go and look at johnwolff.id.au and the article about taking a Marchant Figurematic to pieces, stunning.

Sherlock Holmes:

--- Quote from: woodchips on August 18, 2022, 04:14:20 pm ---Just pulled one of my old mechanical calculators from the shelf to get it running, show to those who have never seen or heard one.

It is a Marchant Figurematic, only because I bought it many years ago less its covers, so already open to inspection. Needed some work to free it off so the motor shaft would rotate and the contacts open to stop the motor. Then I tried putting power on to see if it would run, no. Showers of sparks from the commutator and small cloud of blue smoke. Did try to sort out why but in the end removed the motor and on dismantling the commutator was black from backed on oil. Will need to get in the lathe to clean it up.

But, my question is, after just admiring it whilst drinking a tea, is could you design the calculator using CAD.

For example there are many oddly shaped pieces of metal, but they also have odd lumps and bumps that push other pieces of metal. Also many odd pins that similarly push against or prevent movement of other pices of metal. Then there a springs everywhere, seemingly fixed at any convenient point.

My question is, does CAD allow you to design a particular piece of metal from a key that also understands that there are lumps and pins etc that are interlocks to stop that key being pressed if some other key or operation is in progress. Do you see what I am trying to explain?

The next question is, can you put the contents of the calculator into the CAD program, together with all the interlock and accompanying operations and the CAD package will tell you how the calculator works?

The biggest problem with fixing a calculator is to simply know what each piece of metal does, and when it does it. It is virtually impossible to understand the complexity of the calculator.

Go and look at johnwolff.id.au and the article about taking a Marchant Figurematic to pieces, stunning.

--- End quote ---

I'm sure those who use 3D printers could certainly get into fabricating parts and making something. Did you ever see a Curta? an ingenious cylindrical mechanical calculator, I don't have one, wish I did.

TimFox:
There are some Curtas available on eBay, for roughly $2000 USD.
https://www.ebay.com/b/Curta-Calculators/414/bn_55188475
Nice-looking machines!

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