Brass washer from Contax iiia

[simonOWO]

I was disassembling my Contax iiia to lubricate the focusing helicoid. After reassembling the camera, I was left with a copper or brass washer, and couldn’t figure out where it belongs. Looking back at the photos I took during the disassembly, the washer appeared on my desk sometimes before I taken out the meter assembly from the camera.
Any advice on where this ring belongs?

I didn’t find anything not working after reassembly.

 

[KoNickon]

Under the wind knob perhaps? These sorts of things have a way of being stuck to something else and then separate when you don't notice it, so you're left trying to figure out where they came from.

 

[WoodallP]

Pre-war Leicas seems to have a random number of such washers and sometimes, if you are lucky, you can in figure out where they came from. As KoNickon said they tend to stick and then just fall off when you are not looking, or get stuck to magnetised tools. I’m convinced that some of them may have come from previous repairers rather than the factory.

I think I recall that the Kievs use washers for shimming the lens mount but I could be way off the mark. I realise this is a post-war Contax but it may use the same system.