Square Threaded Insert

A square threaded insert is a bush with a square body that resists turning in soft material. It provides a machine thread in wood, plastic or composite panels.

A square threaded insert gives a strong thread in wood and similar soft materials. It takes a screw or bolt of the same thread, and it often needs a pilot hole and a driver. A washer can spread the load under the head.

This insert is often made in brass, steel or aluminium. The metal body takes the load while the square shape stops rotation.

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 with the order. On receipt, check the square body and thread with gauges. Check that the insert fits the intended hole without forcing.