Riveted joints: Rivets are generally specified in practice by which primary dimension?

Introduction / Context:
Standard practice for specifying fasteners ensures correct selection and interchangeability. For rivets, the shank diameter governs hole size, pitch, and joint efficiency and is therefore the primary specification.

Given Data / Assumptions:

• Conventional hot or cold-driven rivets used in plate joints.
• Holes are drilled/punched to suit the rivet shank diameter plus clearance.
• Other dimensions (length, head size) follow standards once the diameter is set.

Concept / Approach:
The rivet's shank diameter determines net-section area of plates and the shear capacity of the rivet itself. Designers first choose diameter to meet shear and bearing requirements; length is then chosen to accommodate grip length and head formation.

Step-by-Step Solution:

Verification / Alternative check:
Joint design tables list capacities primarily by shank diameter, confirming it is the controlling specification in catalogs and standards.

Why Other Options Are Wrong:

• Plate thickness: used to pick length, not the primary rivet designation.
• Overall length and head diameter: derived after diameter selection.

Common Pitfalls:
Specifying length without confirming grip range leads to improper set and reduced strength.

Final Answer:
Shank diameter