Hexagonal head bolts that feature threads extending only partially along the shank are commonly referred to as partially threaded bolts or partially threaded hex bolts. This design provides a smooth, unthreaded portion, which, when properly positioned, can increase the shear strength of the connection. For instance, a structural steel connection might utilize this type of fastener to ensure that the shear plane falls within the unthreaded section of the bolt, thus maximizing its resistance to lateral forces.
The advantage of these bolts lies in their ability to offer both clamping force (provided by the threaded section) and enhanced shear resistance. Historically, these fasteners have been prevalent in construction and mechanical engineering applications where high loads and precise alignment are critical. The unthreaded portion can also prevent thread damage during installation in certain applications and improve the fatigue life of the joint.
