Simple geared counter (2-digit)?

Any thoughts on the ‘spring’ for the ratchet design I posted?

I have some 1/64" plywood and was thinking of cutting a 1mm strip from that, turned sideways. The range of motion required should only be a mm or two. The arm would then be straight, and I’d glue a half-circle to glue to the end to engage the gear. The 1/64" ply is unfinished, so any number of adhesives would work - probably just use regular wood glue or CA.

Also going to use rings of vinyl as spacers to give me a tiny bit of wiggle room. I have many to choose from but I have some that is as thin as a sheet of paper.

I had better luck with a gravity-fed ratchet, but I don’t think that fits your need here.

I needed strength and was mounted vertically. I think the method you talked about should work. I have done that style before also and it should meet your need.

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Although I suspect your design(s) used thicker material, what did you use for a spring? I would have liked to use a steel spring and ball-bearing, but not much to choose from that’s 1mm in diameter… :rofl: I just cut a small test sample from the same 1mm acrylic and although it flexes just fine, I doubt it would hold up like the 1/64mm ply…

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I was using medium clear acrylic or thick green-glass acrylic. Your materials are thinner, but your design shouldn’t require as much resistance as mine did either. I did have this balanced, using it on each side of the gear, not just in one place.

Are you looking for a nice stop indicator, or are you wanting it to prevent it from going backwards?

The spring was just an arced acrylic arm.

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Yes… it will need to be reversible.

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I don’t know if you figured that out already or not, but I was thinking something like this…
Geneva Mechanism - Layout

Of course this is super simplified and I would prefer to hide the gears (to protect them).

The notches in the ones wheel would be for the stop indicator.

And the Geneva wheel could be smaller if it didn’t need to go to 99.


You could even shift the counting wheels around to change the size of the numbers.
Geneva Mechanism - Layout


Looking forward to getting back to this. Had to read back thru thread to see where I was. Been out of commission again for a while…

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Great discussion to find solutions.

I did want to stick this link in for reference. It does fall into the fairly complicated but Martin Raynsford has a nice one for free download for others who might wish to follow down the deeper rabbit hole.

And here is a simple one. But having a ratchet mechanism would be handy.


it’s fun to read through this and appreciate the collaboration going on.


Just wanted to take a moment to say thank you. I am trying to get back to this project. It’s not crucial but I enjoy the process of designing and assembling little things like this. Your file gave me some ideas that I am trying to incorporate into what I had already come up with, but needed to re-draw due to errors I mentioned above.


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