Definition
A hollow, internally threaded rivet installed from one side of a structure. The Rivnut is inserted into a drilled hole and a special tool pulls a mandrel that upsets (collapses) the back end of the rivet against the blind side of the material, locking it in place and leaving usable internal threads for a machine screw or bolt.
Plain English
A small metal sleeve with threads inside that gets squeezed into a hole from one side of a panel. Once installed, you have a permanent threaded hole you can screw a bolt into, even though you could only reach the front of the panel.
Context Anchor
Seen in aircraft maintenance, especially where covers, panels, brackets, or equipment must be screwed into thin metal that cannot hold screw threads by itself.
Derivation
A trade name formed from 'rivet' + 'nut' — it acts as a rivet during installation and as a nut afterward.
Why Pilots Care
Provides strong, removable attachments in thin sheet metal without welding or access to the opposite side, common in fuselage, wing, and interior work.
Analogy
A Rivnut is similar to a wall anchor used in drywall: it gives a screw something solid to hold onto when the surface itself is too thin or weak to grip the screw well.
Intuition Check
Do not think of a Rivnut as just an ordinary rivet. A rivet mainly fastens parts together permanently; a Rivnut creates a reusable threaded hole for a screw or bolt.
Example Sentence 1
The mechanic installed a row of Rivnuts along the wing root fairing so the cover could be removed and reinstalled with screws during inspections.
Example Sentence 2
Rivnuts were placed along the longerons to secure the interior side panels without needing nuts on the back side.