Thumb Screw

A thumb screw is a fastener with a head that can be turned by hand. It is used where a tool is not wanted for frequent adjustment.

A thumb screw tightens by hand where a tool is not wanted. It takes a tapped hole or a nut of the same thread, and it often has a knurled or winged head for grip. A washer can sit under the head.

Thumb screws are often made in steel, stainless steel or brass. Plastic versions are also common for light duty or electrical insulation.

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 batch. On receipt, check the thread with a gauge and check the head for cracks. Check that the screw turns freely by hand.