I'm designing an automated object capture turntable (take photos -> photogrammetry) where the platform the object sits need to rotate, driven by a stepper.

The catch is the base is glass as I need to view the object from beneath and the bearing sits around the edge of the glass plate, not at it's center.

This is the bearing I'll be ordering, it has a 24" diameter: https://www.amazon.com/gp/product/B071CPFCYS/ref=ox_sc_act_title_1?smid=A2ZKGRENV5NC9J&th=1 enter image description here

Now I need a way to mechanically couple a stepper motor to the inside or outside of the bearing. I'd like to use something more precise like timing belt as opposed to rollers.

Is there an existing product/technique for interfacing large wheels with stepper motors?

Update: As per jsotola's suggestion I did some searching, best thing I could find was this: Scooter Wheel Adapter for 5mm Shaft enter image description here

My origional ideas was to glue gt2 belt around the inside/outside, only just rediscovered the link to my inspiration: Make Your Own Gears Out of Wood and Timing Belts enter image description here

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    $\begingroup$ use a friction drive roller to turn the ring .... or buy two, discard one outside ring, stack the inside rings, use a belt drive to turn the inside ring .... paint timing marks on inside of inside ring ... use optical sensor to detect marks $\endgroup$ – jsotola Jun 20 '19 at 22:49
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    $\begingroup$ Or make your timing marks on the glass and don't use a stepper at all; use a servo motor instead. $\endgroup$ – TimWescott Jun 20 '19 at 23:41
  • $\begingroup$ yeah, i was thinking "no stepper", but i did not say it $\endgroup$ – jsotola Jun 21 '19 at 1:51
  • $\begingroup$ Welcome to Robotics Geordie, but I'm afraid that Unbounded Design Questions are off-topic because there are many ways to solve any given design problem. We prefer practical, answerable questions based on actual problems that you face, so questions which ask for a list of approaches or a subjective recommendation on a method (for how to build something, how to accomplish something, what something is capable of, etc.) are off-topic. Please take a look at How to Ask & tour for more information on how stack exchange works. $\endgroup$ – Chuck Jun 21 '19 at 12:31
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    $\begingroup$ If you're looking for feedback on something, or lists of suggestions, etc., please join us in Robotics Chat - all the off-topic content is welcome in chat. As it stands, though, you've asked for a recommendation for the "best" way to do something, with no criteria on what would make a suggestion "good," and you've supplied an answer in your own question with no explanation as to why that's not a suitable answer. There's no clear answer to this question other than lists of suggestions and so it is not a good fit for the site. $\endgroup$ – Chuck Jun 21 '19 at 12:41

Have a machine shop make you big gear or timing belt pulley that fits over the outside of the bearing.

Note that if you a position reference on the outer edge of the glass you can use encoder feedback and a DC motor -- you should be able to achieve more precision this way.

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