While cleaning my 82 Fuji Supreme (12 speed) I noticed that I lost one of the chain ring bolts and all others were loose. So, I tightened all with a 5mm allen wrench, the same one that fits most water bottle cage bolts. When I try to find a replacement for the lost one on Ebay, I see only M8 bolts.
What is the correct size for my bike?
What is the best place to get them - besides LBS.