A fastener or fastening is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components. Steel fasteners are usually made of stainless steel, carbon steel, or alloy steel.
A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring, wear pad, preload indicating device, locking device, and to reduce vibration.
A bolted joint is one of the most common elements in construction and machine design. It consists of a male threaded fastener that captures and joins other parts, secured with a matching female screw thread. There are two main types of bolted joint designs: tension joints and shear joints.
The screw is a mechanism that converts rotational motion to linear motion, and a torque to a linear force. It is one of the six classical simple machines. The most common form consists of a cylindrical shaft with helical grooves or ridges called threads around the outside. The screw passes through a hole in another object or medium, with threads on the inside of the hole that mesh with the screw's threads. When the shaft of the screw is rotated relative to the stationary threads, the screw moves along its axis relative to the medium surrounding it; for example rotating a wood screw forces it into wood. In screw mechanisms, either the screw shaft can rotate through a threaded hole in a stationary object, or a threaded collar such as a nut can rotate around a stationary screw shaft. Geometrically, a screw can be viewed as a narrow inclined plane wrapped around a cylinder.
A locknut, also known as a lock nut, locking nut, self-locking nut, prevailing torque nut, stiff nut or elastic stop nut, is a nut that resists loosening under vibrations and torque. Prevailing torque nuts have some portion of the nut that deforms elastically to provide a locking action. Free-spinning locknuts exist which carry the advantage of not requiring extra torque until seated.
A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thread on a material too thin to accept it, mold or cast threads into a work piece thereby eliminating a machining operation, or simplify changeover from unified to metric threads or vice versa.
A jam nut is a low profile type of nut, typically half as tall as a standard nut. It is commonly used as a type of locknut, where it is "jammed" up against a standard nut to lock the two in place. It is also used in situations where a standard nut would not fit.
A flange nut is a nut that has a wide flange at one end that acts as an integrated washer. This serves to distribute the pressure of the nut over the part being secured, reducing the chance of damage to the part and making it less likely to loosen as a result of an uneven fastening surface. These nuts are mostly hexagonal in shape and are made up of hardened steel and often coated with zinc.
A well nut is a blind rivet-like type of fastener used to blindly fasten a piece and to seal the bolt hole.
A split beam nut, also known as a split hex nut or slotted beam nut, is a locknut with slots cut in the top that separate the outside end into two or more sections that are bent slightly inward, making the thread diameter undersized in the slotted portion. As the nut is threaded on, these sections are forced back out to their original position and increase the friction between the nut and the fastener, creating the locking action.
A distorted thread locknut, is a type of locknut that uses a deformed section of thread to keep the nut from loosening due to vibrations, or rotation of the clamped item. There are four types: elliptical offset nuts, centerlock nuts, toplock nuts and partially depitched (Philidas) nuts.
A rivet nut, also known as a blind rivet nut, or rivnut, is a one-piece internally threaded and counterbored tubular rivet that can be anchored entirely from one side. It is a kind of threaded insert. There are two types: one is designed to form a bulge on the back side of the panel as a screw is tightened in its threads. The other is similarly drawn in using a screw, but is drawn into the sleeve instead of creating a bulge.
A speed nut, aka sheet metal nut or Tinnerman nut, is a type of locknut with two sheet metal prongs that act as one thread. They are made from spring steel.
A barrel nut is a specialized forged nut, and is commonly used in aerospace and ready-to-assemble furniture applications.
A plate nut, also known as a nut plate, anchor nut or anchor plate, is a stamped sheet metal nut that is usually riveted to a workpiece. They have a long tube that is internally threaded and a plate with two clearance holes for rivets. The most popular versions have two lugs and they exist as fixed anchor nuts and as floating anchor nuts. The latter allows the nut to move slightly and so enlarges the positioning tolerances of the mounted parts. They were originally developed for the aerospace industry but are now also common in automotive racing.
A swage nut or self-clinching nut is a type of nut or threaded insert that is used on sheet metal.
A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a nut.
A nut is a type of fastener with a threaded hole. Nuts are almost always used in conjunction with a mating bolt to fasten multiple parts together. The two partners are kept together by a combination of their threads' friction, a slight stretching of the bolt, and compression of the parts to be held together.
A bolt is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to a matching nut. The bolt has an external male thread requiring a matching nut with a pre-formed female thread.
A security locknut is a type of industrial fastener composed of two steel threaded parts: a nut body and an elliptical spring steel lock ring. Security locknuts are fastened onto a mating bolt to form a bolted joint. Forces of friction, a stretching of the bolt, and compression hold the bolted joint firmly together. The lock ring, once assembled into a counterbore in the nut body, provides clamping force on the bolt while the nut body takes the load. This isolates the loading and locking functions and helps prevent the nut from backing off the bolt. Due to the durable spring steel alloy, the security locknut is fully reusable while maintaining prevailing torque in each application.
