Threaded insert

Manufacturers of ready-to-assemble furniture often ship the parts with threaded inserts and other kinds of knock-down fasteners pre-installed.

People who use sheet metal or sandwich panel or honeycomb sandwich-structured composite often install threaded inserts to spread shear, tension, and torque loads over a larger area of the material.

[4] Threaded inserts are commonly used in plastic casings, housing, and parts to create a metal thread (typically: brass or stainless steel) to allow for screws to be used in the assembly of many consumer electronics and consumer products.

The ultrasonic vibrations melt the thermoplastic material where the metal insert is in contact, and pressure is applied to press it into position.

The material typically reforms around the knurled body of the threaded insert to ensure a good retention.

[6] A thin-walled solid-bushing insert by the trademarked name TIME-SERT is locked in by rolling the bottom few internal thread into the base material with a special install driver which will permanently lock the insert in place.

[7][8][9] Inserts that are self-tapping and lock via friction are more commonly known by the trademarked names Tap-lok or Speedserts.

[10] These inserts provide a convenient means of repairing stripped internal threads.

An example application is engine repair after unintentionally destroying the threads in a socket for a spark plug by over-torquing or cross-threading.