[DonRotolo]

For bolts, we have standardized on 1/4-20, mostly socket head cap screws but also button head allens and hex heads. We also use #10-24 (same heads plus flat head allen) and very limited #4-40 (pan head philips only).

We get every size up to 1.25", then every 1/4" to 2", then every 1/2" to 3" (except the 4-40, we get 1" and 2" only). We stock between 100 and 500 of each size, larger amounts generally at smaller sizes.

Thousands of washers, lock washers, nuts, stop nuts. And several feet of all-thread, just in case.

For rivets, we buy the good ones from Bolt Depot in 1/4" and 1/8", some with steel mandrels, some with aluminum. We have a pneumatic rivet gun too. We have used the Harbor Freight ones in 1/8", they were fine, low-strength areas only though.