10 speed chainrings with otherwise 12 speed drivetrain
 

I haven't found anything definitive on my question: will 10 speed chainrings work on an otherwise 12 speed drivetrain? I'm not asking about SRAM and the flattop chain - I know that won't work. I've seen people using 11 speed rings with 12 speed drivetrains and I've been using 10 speed rings on 11 speed drivetrains, which makes me think it's possible. Thoughts?

Maybe just swap cranks w this forumite:
https://forums.thepaceline.net/showthread.php?t=305633

I'm interested to know the answer to this one. But I don't have a crank to swap.

I'm not interested in a crank swap either. I'm using a Quarq.

10spd spacing is quite different than 12spd. The chain or rings would likely wear faster and likely won't shift as clean either. Unless you are using a 1x narrow wide chain ring then I wouldn't do it YMMV!

10s cassette spacing is indeed different but the chainrings are all 'about' the same width but 11s and 12s a 'little closer together is all. Depending on the 'system'...shimano may be an issue since their LH shifter is so positional, Campagnolo not so much..sram, who knows...probably not.

I am using 10 speed rings with a 12 speed cassette, but that is the only 12 speed component on the bike. I’m using bar end levers in friction mode, rings are 46-34 with 11-34 Shimano hg cassette. I tried an 11 speed chain, it worker poorly. Went to 12 speed chain and all good with crisp, clean shifting. I suspect they will be fine with indexed also. As stated above, the spacing difference is with the cassette cogs.
I think you will have to try it to know for sure.

This sounds right to me, the cassette and chain need to match. As the OP found, I've been using 10s rings from TA on my two all road 11s Shimano bikes, with R8000 and R9100 shifters and derailleur, and it works fine, even though the rings are 44-28.

The space INSIDE the chain links is identical on 10 to 12 speed. The chain is narrower outside. The chainring itself will hold the chain and not cause trouble. However, the spacing between rings is not the same and it is possible that the chain can get caught between chainrings.
Single speed chains have inner width of 1/8″ (3.175 mm).
Multi speed chains, from 5 to 8 have inner width of 3/32″ (2.38 mm).
Multi speed chains from 9 to 12 speeds have inner width of 11/128″ (2.18 mm).