What should the shop head of a rivet be relative to the diameter of the rivet shank?

The shop head of a rivet should be one and one-half times the diameter of the rivet shank. This specification is crucial because it ensures that the rivet provides adequate strength and load-bearing capability in the structure it is joining. The size of the shop head is designed to achieve the necessary bearing area against the material being fastened, helping to distribute the load evenly and prevent damage to the base material.

If the shop head were too small, it could lead to decreased structural integrity, as it wouldn’t properly distribute the forces acting on the rivet. Conversely, a shop head that is excessively large could lead to difficulties in handling or fitting the rivet in tight spaces. Therefore, the specified ratio aims to balance performance with manufacturability in sheet metal applications.