Sprocket alignment guide

I seem to remember that someone created a 3d printed part that would make it easy to tell when the sprocket is pointing straight up. I don’t remember the details and am not finding it in a search.

@bar I think it would be a useful thing to add.

something that clips on the top of the sprocket and has a long, straight edge would help by itself, and be more useful with a level, but if it included a place to attach a weighted string so you can easily see the difference between vertical and where the line is, it would be very accurate

This doesn’t even need to be made specifically for one size sprocket. If it has two pins that straddle one sprocket point it could work with multiple sizes (although you would have to be sure it was really seated well)

another approach would be to make something that has a horizontal flat on it that you would use with an existing angle that you have (or make with the 3/4/5 right angle approach)

The problem is that one encoder step is so tiny, over a 1m length, an error of one encoder step is 0.77mm. We don’t need to try and be that accurate, but the closer we get, the more accurate we will be.

If we could make things precise enough, this is where a vernier scale would be ideal, but I don’t think we would have with a precise enough bearing to be able to make one

thoughts on how this issue?

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@dlang

If you can give me a 3D file, you make something up, I can test it.

Thank you

https://www.thingiverse.com/thing:2621501

Not my work, but I think this is what we’re talking about.

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that’s the right type of thing.

center to top doesn’t give very long baseline for accuracy

It doesn’t need to surround the entire sprocket (ideally it should be parametric
so you can enter the number of teeth)

top to bottom (or extending things out in both directions) would give a more
accurate baseline

or make the top/side flat so you can put a level on it…

also, this should be done with something pulling to try and rotate the gear
towards the center of the maslow (so that backlash isn’t a factor)

It was me who posted the original idea. This is the post Alignment guide
Thinking about what @dlang is saying I have revised the design to have two pin positions so you can hang two ‘plumb bobs’ off a short center pin and a longer top pin, thus when the string’s align you have top tooth vertical. The pin can be anything you have to hand (cocktail sticks or matchsticks?) drill holes to fit them.
Here is one I have just printed to test the fit, I needed to adjust the size of the cog hole to fit tightly on the supplied cog. I have updated the thingiverse model.

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@StephenMcG

Great work, thank you for your contribution.

Thank you

Is it important that one tooth be at 12 o’clock or is it important that a particular tooth is in the exact same spot as it was when you calibrated?

any tooth, the maslow only does incremental tracking of the motor motion, so it
needs some starting point, and any consistant starting point is good.

The convention has been established to put one tooth straight up (so that the