Olympus FL-36 flash unit is a very good one, besides the locking ring being very brittle. Mine broke into bits, so I went to the drawing board. Designed it in two halves, so that I don't have to disassemble the unit.

There are two versions: one with the regular grippy border to be bonded with contact glue, and other one to use 2.4mm zip ties (this was the first one I drew, as I used to hold the original ring with zip ties hoping it would stand, which it didn't. I don't like it, but as I had it anyway, I posted it).

I share STEP files, for anyone to do as needed. The thread is 22mm x 1mm pitch.