Yeah, that's the issue. Jut about all of the ones from this "TOMLOV" brand (and ones that clearly copied them) seem to have the ring and bracket that connects to the pole as one piece. This is apparently an "updated" design too, as I saw others that claimed they were "updated" looking the same, while older designs seemed to have the ring be a separate piece held by two or four screws, like shown here: https://www.amazon.com/Koolertron-Extended-Microscope-Adjustable-Microscopes/dp/B07BFCSXLS/

The issue though is that even if I were to use that bracket to replace it's ring with a 50mm one, almost all the designs have a single large screw in the center, while that one has two or four (I have seen both) screws that would be in the way of the hole of the large screw even if I drilled holes into it for said two/four screws.

There are also bases by HAYEAR themselves, same brand as my camera and lenses, and they do have a 50mm version, but it costs twice as much, is half the height, much smaller base, and no lights.... plus there are odd slots in the base that seem to indicate it was originally meant for something else: https://www.amazon.com/HAYEAR-Industry-Stereo-Digital-Microscope/dp/B07GPCQWXK/

I was originally seeing if I could get this just to harvest the bracket from it since it seems to use a standard one-screw removable ring design: https://www.amazon.com/HAYEAR-Endoscope-Magnifier-Microscope-Aluminum/dp/B07ZF2VV48/

But then I noticed that the grooves on the pole are diagonal, while the TOMLOV one I posted are straight. Seems that most designs either use that diagonal teeth design... or just a smooth pole line in that HAYEAR one I posted. About the only ones that use the straight teeth are either the ones without a replicable ring or the two/four screw ones.

This does make me wonder if at least the part of the pole that screws into the base is standard so I can replace the entire pole.

Sop far it seems like without more information on what is and is not standard, and if any of these parts are interchangeable between the different stands I have no idea what my options are.

As for how good I am with cutting, not very. I do have a Dremel, but no real professional such tools and not too much experience, though I have others I can ask for help that at least have some experience. This was a route I was considering too, if I could just simply cut the dang thing off in the same shape that standard replicable rings are so I can then put a 50mm on it myself. But cutting the ring off seems the easy part, the hard part seems to be finding a way to fit a screw into that solid block of metal between the ring and bracket.

I can get the 7.3 inch version of this one used for $17, and in the pictures it has a replicable ring, so maybe I can also do that. If the bracket itself isn't compatible, maybe the entire pole itself will be and I can just put the entire pole/bracket/ring assembly onto the base: https://www.amazon.com/Koolertron-Extended-Microscope-Adjustable-Microscopes/dp/B077ZN85VW/

I can't believe the hardest part of this is not finding the a decent compatible camera, lenses, or even a screen for a decent price (Using a TV for now, but there are many 6-10 inch screens in the $40-70 range meant for a Raspberry Pi that have HDMI inputs)... but the base of all things.