Rivets

The essentials

A rivet is a permanent fastener: a short round rod with a head at one end. It is passed through holes in the plates and the protruding end is hammered or pressed to form a second head, clamping the plates together. Unlike bolts, rivets cannot be removed without cutting them. Riveted joints are used in structures such as bridges, tanks and ship hulls, and in sheet-metal work.

Key points

• Parts of a rivet: head, shank (body) and tail (the end from which the second head is formed).
• Snap (cup or button) head: rounded head, the most common type. Usual proportions: head diameter 1.6D and head height 0.7D.
• Pan head: shaped like a frustum of a cone; strong, used in heavier work.
• Flat head: a thin, flat cylindrical head; used where only a small projection is allowed.
• 60° countersunk flat head: conical head that fits a countersunk hole so the surface stays flush, e.g. where smoothness is needed, as on ship hulls.
• The hole is drilled slightly larger than the shank so the rivet can be inserted while hot or cold.

Exam tips

• Sketch the head in two views (front and top) in correct proportion to the shank.
• Remember that the countersunk rivet head angle is 60°, while the countersunk screw head in this syllabus is 90°.

Common mistakes

• Treating rivets as removable fasteners.
• Drawing the snap head as a full hemisphere of diameter D.