Countersunk Socket Screws - CSK Allen Screws | Bolts - Fasteners - Orbital Fasteners.Also known as a flat-heat screw, a countersunk screw is a type of screw that's designed to rest flush with the object or surface in which it's inserted. They are called “countersunk screws” because they “sink” into objects and surfaces. They feature a flat head that tapers along the shaft.
A countersunk screw head, also known as a flat head, has a flat and level head. The aim of the countersunk screw head is to allow the screw to be level, or beneath, the surface it is being screwed into. A bugle screw head is very closely similar to the countersunk screw.