You can make rivets out of small carriage bolts. I did that to make replacement rivets for the rear fenders.
I had to reshape the heads to match the originals by putting them in a cordless drill and dressed them into shape on a bench grinder, then polished them on 400 grit sandpaper while still in the drill.
I didn't set them like rivets. I just used a nut and lock washer underneath where no one will see them.
Carl
