Is it possible to tighten the friction pinion on the 11AO* series movements? It has this oddball setup with a brass washer that sits in the cutout at the top of the friction pinion:
I've tried closing the hole with two round faced stumps but without any success:
I've also tried the same on the brass washer but it didn't close the hole it just widened the washer. I don't know why they didn't just use the 11AN* friction pinion as that one interchanges with the 11AO* and is easily tightened.
If anyone has a method to tighten these it would be much appreciated.