Monosert & Duosert Insert

A Monosert or Duosert insert is a threaded bush for plastics and composites. It gives a strong machine thread in a moulded part so the joint can be taken apart and refitted.

A threaded insert repairs or reinforces a tapped hole in a softer material. It takes a matching screw or bolt of the same thread, and it often needs a drill and a tap for fitting. A key or a driver can set some types.

These inserts are often made in brass or steel. Brass gives good heat transfer for thermal insertion, while steel suits higher load.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance and a dimensional report. On receipt, check the thread and the insert length against the drawing. Test a few inserts in a sample boss to confirm they hold.