Unless the material is very soft, flat and oval heads require a countersunk hole. Sometimes features are combined, as in the case of slotted hex, hex washer, slotted hex washer and round washer head designs.Ĭountersunk designs mainly consist of flat, oval and bugle heads.
This style includes: binding, button, cheese, fillister, flange, hex, pan, round, socket and low socket, square and truss heads (binding head is occasionally referred to as binder head). Non-countersunk heads-where the head is fully exposed-encompass the largest variety. There are two basic designs: countersunk and non-countersunk.
Understanding the differences will help you decide which style to choose. Sometimes the style serves a functional purpose, and sometimes it's more decorative in nature. Screw type fasteners are manufactured with different head styles. Fastener Tech Data | Understanding Series Introduction
