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A bolt is a threaded fastener that clamps two or more parts together, usually with a matching nut or a threaded hole.

Tightening the bolt stretches it slightly and creates a clamping force that holds the joint firmly against vibration and load; the grade marking shows its strength.

Bolts are used throughout a commercial vehicle. The correct bolt matches the thread size, length, strength grade, and the specified tightening torque for the joint.