The Fastener Superstore carries a variety of screws that are suitable for many applications. They are available in a variety of finishes including black oxide and oil, mechanical zinc and zinc-bake Cr+3. Screws are categorized by their diameter (the threaded portion), head type and drive style. The head style usually dictates whether the screw should be countersunk or not. It also determines whether the screw has a hex socket or not, as well as if it’s serrated. Finally, it determines whether the screw is a standard socket cap screw or a button head socket cap screw.
Button head socket cap screws are a high strength fastener that offers a more finished appearance than standard caps. They have a low, domed head and larger bearing surface that make them ideal for applications where a neater appearance is required. Additionally, their large socket driver face distributes force more evenly than a standard socket cap screw so they can be used in thinner materials.
The majority of machine screws have a hex socket or Allen drive recess. This allows the screw to be turned with a tool such as an Allen wrench (hex key). Other drive styles include slotted, Phillips and a combination of both (Phillips/slotted), plus pan, fillister, truss and button heads. The screw’s length is typically measured from the point where it sits flat on the surface to the end of its threads, although some screws, such as those with a torx drive recess, are measured from their undercut, or starting point, to the tip of their threads. button head screws