These are Rolyn part # 90.0025.
About 300 degrees of rotation gives 1.25 inches focusing travel.
One is stamped No 37 made in England.
ID is 2.5 inches threaded 24 tpi with an internal lip ID 2.46 in.
With a sleeve would make a nice 2" or bigger focuser.
I got these (used? they look new) from BSC optics in Albuqureque
and bought the mounting flanges from Rolyn seperately.
Was for a big bino project that came to nought.
Rolyn wanted hundreds for these things, but a cn-note each is too much.
Sol Lets try $70 each and I'll pay the shipping anywhere in US.