Printed a selection to try out, have not tried it yet but printed fine.

Printed a selection to try out, have not tried it yet but printed fine.

Perfect, thanks! This is like my most simple, yet bet downloaded model ;)
Printed this for a Danfoss Ally mounted on a Hertz M28 valve. The TRV already comes with a M30 adapter, and this ring fitted perfectly to get it down to M28. Had to break it when I wanted to remove it. The pin length is fine, but the hole is a little too small for the Hertz valve, so I made it bigger. Overall this model fits perfectly, and uses next to nothing material. Unfortunately I found the Danfoss to be really disappointing (for thay price especially) so I sent it back. I would definitely recommend this ring for any TRV that comes with a M30 adapter (edited)

Tight fit but it works. Didn't need the pin adapter in order for it to work.
Thanks, this works great! It took some time to get the tolerances right due to the very tight fit (I scaled x and y of the ring to 100.5% with 0.12 mm hole horizontal expansion).
For the combination of Bosch Smart home thermostat and vintage Herz valve I reduced the pin height by scaling z to 65% (the original was too long for me).
Thanks a lot ! It works