What is the length of contact between two mating parts in screw and nut threads called?

The term "Length of engagement" refers specifically to the length of contact between two mating parts, such as a screw and a nut. This measurement is critical in applications where threads are involved because it influences the load transfer, strength, and overall performance of the connection between the screw and nut.

The length of engagement is essential for ensuring a secure fit and determining how much axial load the joint can handle without failure. A longer length of engagement typically leads to greater resistance to stripping and enhances the joint's overall reliability.

Other terms, while related to contact and engagement in mechanical systems, do not specifically denote the length of contact in the context of screw and nut threads. Consequently, understanding the "Length of engagement" provides critical insight into the mechanics of threaded connections and their effectiveness in machine design.