What is grip length on a bolt?

• A. The portion of the shank under the head that is not threaded
• B. The threaded portion length
• C. The entire length of the bolt
• D. The distance from the head to the tip

Answer: (A)

Grip length is the portion of the bolt shank under the head that is not threaded. This unthreaded section lies between the underside of the head and the start of the threads and is what actually clamps the parts together. The threaded portion engages the nut or a tapped hole, so it isn’t grip length. The distance from head to tip describes the overall length of the bolt, not the grip length. Proper grip length ensures enough unthreaded shank to clamp the parts while leaving sufficient thread engagement for the nut or threaded hole.