Hex Head Screw With Captive Washer

A hex head screw with captive washer is a screw with a washer that stays on the screw shank. The washer cannot be lost during handling or assembly.

A hex head screw with captive washer fastens parts through a drilled hole. The washer stays on the screw and spreads the load under the head. It takes a nut of the same thread and class, or it can thread into a tapped hole.

This kind of screw is often made in carbon steel or stainless steel. Carbon steel is usually plated for corrosion resistance, while stainless steel is chosen for outdoor or wet areas.

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 to JIS B1187. On receipt, check that the washer turns freely but does not come off, and that the thread and head are undamaged.