I've been working on Vespas and I dug around under 30 years of junk in my garage and come up with a big container of metric nuts and bolts. So far, I have found the ones I needed, but I'm confused by the marking on them. I can't find anything that has much to do with the size and thread of the bolt, and I'm not even sure that I'm reading the grade markings right. For example, I found bolts 6, 8, and 10 millimeter sizes, but nothing on the head mentions these numbers. What does all this stuff mean?

8 mm bolt, head takes a 12 mm wrench, marked 4 on the head
10 mm bolt takes a 14 mm wrench marked 3
8 mm bolt takes 13 mm wrench marked Berner 8.8
10 mm bolt takes 17 mm wrench marked metric E1
10 mm bolt takes 15 mm wrench marked 9.80
6 mm bolt takes a 10 mm wrench, marked 7

Then there is stuff like an 8 mm that takes a 13 mm wrench, and has the word "metric" at the top, a picture of an anchor in the middle, and three little dashes at 3, 6, and 9 o'clock. I also found head markings of "10.9," "er 8.8," and "ORV 80."

Unlike some Americans, I am very comfortable with the metric system and use it all the time, so there is a chance I will understand an explanation.

I think it is possible that they came from Italy, Germany, and Japan. Some of the markings may be trade marks. Can anybody explain this mess to me?
Thanks,
How"RinkWorks; *the* place for information"ard