Frame Bolts
Frame bolts are a one-piece hex-washer head bolt with a flat bearing surface. They have an integrated flange underneath the head that distributes the load over a wide area. They are also known as hex flange screws, heavy truck frame bolts, and chassis bolts.
Frequently Asked Questions About Frame Bolts
What are frame bolts used for?
Frame bolts are frequently used on truck chassis or frames, which is how they got their name.
What’s the difference between a frame bolt and a hex bolt?
The main difference is the flange. It acts as a built-in washer on a frame bolt, and therefore eliminates the need for a washer. It is nonexistent on a hex bolt, and therefore a washer is needed when using one.
What sizes are available?
AFT offers frame bolts in both metric and SAE sizes. Diameter thread sizes range from 1/4”-20 to 3/4”-16, or M5-0.80 to M16-1.50. Lengths range from 3/8-6” or 8-150mm.
What grades and materials/finishes are available?
AFT offers frame bolts in a variety of grades, including Grade 5, Grade 8, Grade 9, Class 8.8, Class 10.9, and Class 12.9. They are made of either steel or alloy, and come in a wide range of finishes, such as black phosphate and oil, furnace black, trivalent RoHS, Zinc Cr+3, Zinc Yellow, and Zinc Yellow Bake Cr+6. We also offer a larger variety of custom coatings via our in-house plating department.
Do frame bolts come with nuts and washers?
Frame bolts do not come with washers, as the flange eliminates the need for one and helps compensate when the holes are misaligned. Frame bolts do need nuts, however they do not come with one. Grade-G lock nuts are commonly used with frame bolts, as it helps resist bolt slippage by distributing the clamp load over a wide area.