Need help finding something. I am again working on the restoration of an Antique Woodbody Car. Trim was held on with Ovalhead Brass screws (not a problem) and they were set in small cup washers to prevent them from working their way too deep or waller out the holes under constant vibrations. I can't seem to find these washers although I know they are out there but where, was hoping some of you guys have run across them Here is a crude drawing of what I am looking for.... thanks and hope you can help.
Thought maybe they might be in some Marine supply but no luck yet, perhaps if I knew the real name of them it would help in the research... Any help appreciated.