The shaft on the rivets was cut down after they were fitted at the factory so I don't know the original length, however measuring just the length of the shaft on the rivets (not including the rivet head) off my bike the longest length is 12mm and the shortest about 8mm, so I'd say you want a minimum rivet shaft length of 15mm and then cut them down after fitting them. On the rivet material, I'm hopeless at metallurgy and now looking at the rivets in daylight they appear to be some sort of silvered coloured alloy metal.
Have you thought of using rivnuts, these give you a thread you can screw into. Vatrious sizes available, from eBay, screwfix etc. If using in plastic / GRP, dont over tighten when fitting to prevent cracking the parent material. These are fitted with a bespoke tool, about £20 similar to a pop rivet gun.
Bit of a resurrection of this thread. I have been able to replicate these rivets to my satisfaction. If anyone is in need, feel free to contact me. I chose to have zinc plated backing plates but I can do them in the burnished steel too.
Absolutely brilliant work. Huge 'shout out' to forums for the invaluable anally retentiveness hidden within.
