Last month I found this combination that works great on Asahi Pentax 60mm and Asahi Jupiter 60mm scopes, apologies for the delay in posting. 1.25" adapter from SVBONY with a 42mm thread, then a 42mm-37mm step ring, then right onto the focuser barrel.
Again, only a couple of threads holding the step rings in place, so I'm not using a heavy diagonal or eyepiece. But it works great with a light payload. Non-marring setscrew is nice on the SVBONY.