SCREWS
Flat Screws
A Flat head screw includes a flat head and a shank with threads. The flat head is integral with a coupling end of the shank and includes a top face and a bottom face. A socket is defined in the top face and extends through the bottom face into the coupling end. The coupling end includes an enlarged coupling section having a top end contiguous to the bottom face. The enlarged coupling section further includes a lower end with a tapered section. The threads extend to the enlarged coupling section. A minor diameter of the threads on the enlarged coupling section is greater than that of the threads on the remaining portion of the shank by about 5-25%. A length of the enlarged coupling section is greater than at least one pitch of the threads for forming at least one thread on the enlarged coupling section.
Hex Head Screws
Hex Head Screws are cap screws with a hexagonal head, designed to be driven by a wrench (spanner). An ASME B18.2.1 compliant screw has somewhat tighter tolerances than a hex bolt for the head height and the shaft length. The nature of the tolerance difference allows an ASME B18.2.1 hex head screw to always fit where a hex bolt is installed but a hex bolt could be slightly too large to be used where a hex head screw is designed in.
Pan Head Screws
Pan Head Screws have a low disc with chamfered outer edge.
