I've just received a 130mm f6.8 Dagor from ebayer Cupog. The shutter speeds were uniformly very slow, so I took the lens off the attached lens board, unscrewed the piston caps, and swabbed the cylinder out with several cotton swabs. Reassembled--problem solved. However, when I went to put the lens back on the board, the retaining nut cracked off at the spanner wrench slots at 12 & 3 o'clock. It looks to be cheap pot metal in the nut. Maybe they had a shortage of good steel around WW1 when the lens was made. Anyway, the nut will tighten somewhat, but I don't want it breaking again. Is there a source for replacement nuts? I had another idea: dab some latex caulk or silicon rubber gasket goo around the back of the shutter (fairly small amounts) and then tighten up the broken nut. Any advice here? Other than this problem (which I've never had before), the lens is in excellent shape! Thread diameter of the shutter (where nut attaches) is 32.25mm.


Kent in SD