threadbearing

Threadbearing is a term sometimes used in mechanical engineering to describe the load-bearing capacity of a threaded engagement—the portion of a bolt, screw, or threaded stud that is in contact with a nut or tapped hole and carries clamping or service loads. It is not a universally formal term in standards literature, but it is used to discuss how load is transmitted through threads and how the effective bearing area influences joint strength and stiffness.

In a typical bolted joint, the clamping force from tightening is transmitted through the bearing contact between thread surfaces and the mating part. The load is resisted by bearing stresses at the thread roots and by shear along the engaged threads. The distribution of these stresses depends on the engagement length, thread pitch, fit class, and material properties. Longer thread engagement increases bearing area and can improve load-carrying capability, but the benefits depend on the material pair and overall joint design.

Design considerations for threadbearing include ensuring sufficient thread engagement length for the materials and loading involved, avoiding damage from over-tightening, cross-threading, or corrosion, and accounting for lubrication, which changes friction but not the geometric bearing area. Engineers rely on published standards and guidelines to determine minimum engagement and appropriate thread fits for different material combinations, ensuring that the threaded connection can develop the intended strength without premature failure.

Overall, threadbearing relates to how effectively the threaded portion of a fastener distributes load within a joint and is a key factor in assessing the strength and reliability of threaded connections.