bolt depot use to sell truss bolts, similar to button head, but a bigger head. i don't see them in the catalog anymore. i used 3/8'' ss truss bolts on the fender to bed connections and 1/4'' ss truss bolts on the steps. they have a slot or phillips head but look good. no closeup pics of bolt heads
nothing to do with your original question... but when looking at boltdepot site i found
flange bolts. didn't know they were called that but it's the bolt that holds 90% of our trucks together. i sandblasted and painted all my old bolts, had i know about flange bolts i would have ordered a box of 100 5/16x1 flange bolts. they have the serrated head that all of the bolts have
