TLDR, need chain ring bolt for old 80s? roadbike. Puch Pathfinder 10 speed. Sugino crank? Seems to not be a common size. Pics (apparently Im not allow to upload pix for you to see the bolt...) Youtube search "Vintage Bike Chain Ring Bolt ampecsu"

Hi I'm new here...
I just bought an old Puch Pathfinder 10 speed that I've noticed was missing a single bolt after the chain kept popping off after initially riding fine for 15 min... Guess I wasn't thorough enough in inspecting it at purchase. It may have been jb welded prior.

Anyway, I've been to 3 local shops and none have anything this small in diameter and 2 recommended that I try a recyclery that is possibly due to reopen this month.

Any leads or tips on finding this bolt or another solution? I've checked ebay. The crankset says Sugino if it matters.

Thanks