I disassembled the front components of my Nikkor 300mm/f9, Schneider Super Angul on 90mm/f5.6 and Rodenstock Sironar 150mm/f5.6 Apo at the same time and after cl eaning the lenses I found a very thin brass washer on the table. I also found an identical one in place in the Copal # 0 shutter of the Super Angulon and there is no washer in either the shutter of Nikkor or Rodenstock. I am sure the washer that came off is not from the Nikkor which has a No. 1 shutter but I am not sur e should it go to the Rodenstock so that it has one washer too, or should it go to the Super Angulon so that it has two washers. I am also wondering if I had lo st one larger washer for my Nikkor. Thanks for your advice in advance.