Sometimes it's a tip (as small as 1mm long) of broken cable release that stays screwed in. Use a magnifying glass and check carefully. If not, try to find bargain lens (whatever brand and focal length, with fungus, separation and scratches all-together) with same/similar shutter and replace the socket.
In the OP's case if it was me I'd remove the stripped one from the shutter and re-tap it with a straight tap then use one of those Rowi.Kaiser type 90 degree adapters and glue it into place before screwing the part back on the shutter casing.
I use an M4 x 0.7 tap on the Thornton Pickard release arms and that seems the best overall fit, I can use a size up or down because of the taper.
My experience is that there's quite a variation in the threaded end of cable releases, I had some that would only fit a Prontor and no other camera/lens.
The Rodenstock 210/5.6 lens most likely uses a Copal #1 shutter.
The Copal #1 replacement socket is $39.95 at B&H in NYC.
Originally Posted by AgX
Originally Posted by Ian Grant
I just checked it.
Though the Standard M4 thread has a too steep pitch, due to the still small height of thread contact and the larger diameter of this contact this 4 x 0,7 size gave the best overall fit. At least for a provisional solution a DIY thread cutting attempt should be done.
Originally Posted by Ian C
Exactly what i needed! awesome dude :D
i appreciate the blast of knowledge fellaz, i went on and found a copal no.1 shutter and swapped the socket!
now i can use my Rodenstock apo 210mm like it was intended!