Flange bolts have a circular flange under the head that acts like a washer to distribute the load. Flange bolts that are non-serrated are sometimes called frame bolts.
A hexagonal head for use with a wrench. (Note: Shorter lengths are found under full thread.) These bolts are sometimes called Frame bolts. Meets IFI-111 (2002).
Grade 8 is stronger than grade 5, and is commonly found in high strength automotive applications. A tempered medium carbon steel. Zinc plated for moderate corrosion resistance.
Flange bolts have a flange on the bottom of the head that distributes the load like a washer.