Fastener

I'm afraid I don't know what this screw might be. Can you clarify where it installs? Are you saying it goes in the "elbow" of the operator arm, as per your other two photos?

If so, this might be our 62-014B rivet. These aren't screws, but rather rivets that hold the two arms together. You install them by placing it in the hole with the two arms, then hammering it over a metal plate so that it "mushrooms" out.

If I'm off base, please just clarify what this is and we can work from there.