Most everything you use or look at has something or things’ to hold it together. What is a fastener? Well, they keep things together usually in non-permanent fashion as you can replace it with a new one or a different kind of fastener. What are they called specifically? Screws, bolts, nuts, washers, speed nuts, cotter joint those kinds of things. Without fasteners, your car would rattle apart, the airplane you board on would never get off the ground. Yes, fasteners are essential and they are a fact of modern industrial life. Just as fasteners have different names and purposes, they also are made of different materials.
Some examples are carbon steel fasteners for cars, oil and gas production and shipbuilding, heavy industry types, and there are different types of carbon fasteners depending on the use. Then there are stainless steel fasteners which have lower carbon content used for a wider variety like cars or in your house.
Aluminum fasteners are lightweight for certain specific jobs. Titanium fasteners are suitable for high temperatures for use in things like planes, petrochemical companies, and race cars. There are brass and bronze fasteners that serve a purpose due to non-magnetic properties but mostly used for decorative purposes due to cost. There are even non-metallic fasteners that have a limited purpose due to their low strength. Depending on use fasteners may have any number of coatings on them to prevent corrosion. Chromium, zinc, phosphate, nickel, silver, cadmium, and black oxidizing layer are some examples. There is all manner of fasteners depending on need.
There’s the old fashioned wood screw that can hold material together with a vise-like grip. Countersink screws perfect for woodworking as the screw head drops below the surface to give that polished look. Self-tapping screws are another innovation for specialized use. The self-tapping screw can penetrate the material and create its thread to hold itself in place, usually for as long as needed. There’s the deck screw for building decks; hex lag screws also used for wood to hold machinery in place — sheet metal screws with sharp cutting threads to anchor into metal, plastic or wood.
When regular screws aren’t enough, bolts are an everyday staple in cars and household appliances. They come in two parts, washer and nut. Threading the bolt through the washer and nut makes for a sturdy fit. Of course, there’s a variety of bolts to fit most any job — the carriage bolt with a squared section to hold the bolt in place. The hex head bolt usually installed with a wrench. The machine screw often used with washer and nuts. The shoulder bolt which has a dual purpose as it has a slender top for use as a shaft for other moving parts. The socket cap screw installed with a socket wrench. The set or ‘grub’ screw has no head at all and the square head bolt which offers more torque.
To complement the various screws are the variety of nuts — the speed nuts which can replace the washer if needed. If speed nuts don’t meet your need, there’s the cap nut with its rounded head to cover the screw thread — castle nuts used for things like wheel bearings. Coupling nuts can thread two screws together when necessary — serrated flange nuts that have a built-in washer of sorts to hold the nut in place — several types of hex nuts usually installed with a wrench. There’s a variety of locking type nuts, which as implied lock themselves in place.
Most of the nuts rely on some washer to make themselves complete. The variety of washers is comparable only to the type of nuts and screws they fit on. And don’t forget about the various rivets, concrete anchors, inserts, and retaining rings to balance everything out.