Bolts
Bolts are a very common mechanical fastener type used for joining components together, and they are regularly paired with a nut and washer for load distribution. With a head on one end of the fastener, a typical bolt will feature external threading that may spana distance across the length of the shank. For installation, the tail-end of the bolt is passed through the pre-formed hole of a component, and a matching washer and nut may be tightened on the other side to clamp objects together.
Coupled with a nut, a
bolt assembly applies axial clamping forces on the installation while the shank pins the joint with sideways shear forces. It is important that the bolt is correctly sized to both match the length and diameter of the hole. Meanwhile, all washers and nuts should also match to secure a reliable connection. Lastly, the correct tool for installation should always be used to avoid damaging the head slot and proper torque values must be followed.
Screws
Screws are fasteners that are regularly compared to bolts due to their similar appearance of a threaded shank with a head on one end. Their difference, however, lies in the fact that a screw may bore its own threading into a component for installation, and they do not require nuts for securing assemblies. Due to the helical threading of the screw, the fastener is capable of pulling materials together during installation to prevent easy pull-out.
To install a screw, the head portion will regularly feature a slot that allows for a tool to be used for twisting and tightening the component. The head is also important for ensuring that the component is not driven too deep into the installation so that a bearing surface is maintained. There are many screws that may be used for creating an assembly, and common variations include wood screws, machine screws, sheet metal screws, thread cutting machine screws, and socket screws.
Nuts
Nuts often come in the form of hexagonally shaped steel components that feature internal threading. As discussed before, nuts are almost always used with a correlating bolt for the means of fastening parts together. The hexagonal shape is the most common as it provides optimal granularity of angles so that tools may achieve sufficient torque even in tight spots. Depending on the application and its various factors, numerous nut types exist such as nylon insert lock nuts, jam nuts,
wind nuts, cap nuts, flange nuts, and tee nuts.
Washers
Washers are most often found in the form of thin, disk-shaped plates that have a hole in their center. Typically, a washer is placed between a nut and a bolt, allowing for it to help distribute their loads properly. Beyond such applications, washers also reduce friction, mitigate corrosion, maintain tension, and may serve as a spacer. Depending on the need, common washer types include plain, spring, and locking washers.
Studs
A stud is a rod or shaft that is headless, and they typically feature external threading on both sides and may have an unthreaded section in the middle. Studs are regularly chamfered at their ends, and this allows for nuts to be attached and tightened to either side as needed. A stud is a beneficial fastener type when the length required for an installation is unknown, and they can have uneven diameters at each end. To ensure proper installation, the stud should be long enough that nuts can be installed while retaining an extra 2-3 exposed threads on the end. Studs can be very useful fasteners for heavy-duty applications as they provide more accurate torque values during installation as they remain stationary during tightening. Additionally, their clamping forces are more even and accurate due to their design.
