Hex Flange Bolt

Hex Flange Bolt


Hex flange bolts are used on vehicle frames, especially truck frames, and anywhere a hex washer head bolt is needed. The large bearing surface distributes clamping force over a large area, allowing them to be used with irregular and oversized holes. Hex flange bolts are often used with Grade G Flange Style Lock Nuts to create a bolt/nut system that resists loosening and spans a wide area. They are also known as: hex frame flange bolts, hex washer frame bolts, hex flange screws. Serrated hex flange bolts have teeth under their head that grip the mating surface to resist loosening.
Flange Bolt, Serrated Hex Threads are standard right-hand. Hex and 12 point are available in Unified inch coarse series (UNC, Coarse) and Unified inch fine (UNF, Fine); serrated hex in Unified inch coarse. Flange bolts are partially and fully threaded depending on size and length. The point for hex types is chamfered or rounded.Measure length from the underhead flange bearing surface to the threaded end of the bolt.
Metric Flange Bolts have a hex head, protruding flange, a smooth bearing surface and coarse machine screw threads. Materials include Class 8.8 and 10.9 steel and stainless steel. Plain finish and zinc plated are available. Also called Frame Bolts and Flange Screws, use with Flange Nuts especially when holes are oversized.
The flange bolt should be long enough to allow at least two full threads to extend beyond the nut face after tightening, which ensures full thread engagement with the nut. Conversely, there should be two full threads exposed on the head side of the nut to make sure the nut can be properly tightened. More exposed threads within the grip (the area between the head and nut) will result in a "springier" bolt. It is also recommended that threads not be in the shear plane(s).