Mystery clutch noise

[1939mars]

I have been chasing a noise related to depressing the clutch and am basically out of ideas. Transmission has been rebuilt and new throwout bearing, pilot bushing, pressure plate and clutch disk are in. Noise persists

It makes the noise when the clutch is depressed. You can get the throwout bearing spinning a little before the clutch is in far enough for the noise to start.

Once suggestion was that the ring gear was not seated on the flywheel. An initial check did not reveal anything but I have not looked through the starter yet. No discernible axial movement of crank.

I've tried to put a link to the noise here:
https://www.scottdoudrick.com/37-noise/

-Scott