The Omnipresent Steel screw
Steel screwan invention that has revolutionized the art of construction. There are a number of steel screws, especially stainless steel screws in use these days. Some of these stainless steel screws are Painted Head Screws, Sheet Metal Screws, Deck Screws, Lag Screws, Machine Screws ,Set Screws, Socket Cap Screws etc.
Basically a screw is used for holding all sorts of things together including wood, plastic and metal. Screws are amazingly versatile. Different varieties have been developed for effective solutions to particular kinds of construction work. They come in different head shapes and sizes. A Pan Head is a standard screw head profile with average diameter and average height, a Button Head is similar to a pan head but with a curved top. A Round Head is a more pronounced head than a button head, a Flat Head has a flat top with a tapered underside that is intended to be driven into a countersunk hole, an Oval Head is tapered underside like a flat-head, but with an oval top, a Truss Head has large-diameter heads with a low profile and a Fillister Head has a thick profile with a slightly rounded top.
There is also a large variety of screw bodies. There is the Wood Screw which is used in wood. The threads are usually coarse and deep to help it grab the wood. The Machine Screw has finer threads than wood screws. It is designed to be used in conjunction with a nut or tapped hole. The Sheet Metal Screw is usually short and has coarse threads designed to grab onto relatively thin sheet metal. The High-Low screw has two sets of threads with alternating heights. High-low screws are specifically designed for certain plastics and other low-density materials. The Self-Tapping or thread-forming screw features threads designed to tap itís own holes. It works well in softer materials such as wood and plastic but is not suitable for harder materials.
Screws are made out of different materials. They can be made out of stainless steel, steel, brass, aluminum, nylon, plastic, etc. They have various finishes such as black oxide or non-stick coating; zinc plating. If rusting of screws is to be prevented they must be galvanized. That is one advantage of stainless steel screws.
Steel is made resistant to corrosion by alloying it with another metal, zinc. When steel is immersed in melted zinc, the chemical reaction permanently bonds the zinc to the steel through galvanizing. Therefore zinc doesn't just coat the steel; it actually permanently becomes a part of it. Steel is popular also because it can be recycled and reused 100%.
Thus a steel screw is the most reliable kind of screw around. All that needs to be done is itís galvanization. Most steel screws used are stainless steel. They may be used in conjunction with different driving methods such as a phillips flat head screw or a phillips button head screw.To prevent corrosion it is best to use a steel screw.