Insert

  1. A metal section (usually brass) with internal threads and external projections, used to provide reinforcement for threaded fasteners in plastic parts. See inserting.
  2. A piece of wear-resistant material bonded to the face of a horn (e.g., titanium carbide).
  3. A metal section threaded both externally and internally, used to repair or reinforce internal threads. Example: Heli-Coil.