Bolts are a type of fastener that is very closely related to screws. While screws directly hold onto the surface they are threaded into, bolts usually require a nut. Usually made from a metal of some kind, it has a head at one end and a chamfer at the other. Its shaft is characterized by an external helical ridge known as a thread.
They have machine threads like screws too. They are used to hold workpieces, or objects together. Bolts have a quite simple construction but feature quite a few parts.
All of these parts are essential to the functioning of the bolt.
Head
The head is the top, flat part of the bolt. It works as a gripping surface tool can grip on to. Appropriate tools must have the corresponding bit to grab onto and tighten or loosen a bolt. Most bolt manufacturers, however, provide bolts with a wrench-type head. Or to put it differently, most bolts can be tightened or loosened with a wrench.
Types of Head
Some bolts come with a screw-type head too, where the bit is at the centre of the head. Some of the most common types of bolt heads include:
• Square shoulder: This type of bolt head come with a truss head. It is shaped that way to allow it to fasten with the minimum amount of surface obstruction. These types of bolts have a square shank which resists rotation.
• Indented hexagon: These types of bolt heads have an indent on their head in a circular shape for use with a wrench.
• Indented hexagon washer: This type of bolt head is almost the same as an indented hexagon. The only difference is that it has a section for a washer at the base. This washer section protects the assembly finish from the head.
•Trimmed hexagon: This type of bolt head features the standard type of head. The only difference is that the corners of the hexagon are trimmed to close tolerances.
• Hexagon Flange: This type of bolt head is similar to the indented hexagon washer. The only difference is that the washer is conical or slightly rounded.
Shank
The shank is located below the head. It is the smooth part of a bolt that lacks any threading. It is made that way to avoid radial movements of the joined surfaces. Bolts that lack shanks have a greater chance of getting loose. Some workpieces that produce vibration, or are exposed to vibrations can come loose.
The shank prevents that from happening. The lack of a shank will mean that the bolt would be completely threaded from below the head to the tip. In that case, vibrations can cause it to spin on those threads and ultimately, loosen up.
Threading
All bolts and even screws have threading. Threading is what allows bolts to be driven in or out of workpieces. Most bolts don't comprise totally of threading, however. They have a head that is followed by a shank and then comes the threading. Depending on the type of bolt, some may have a shank that is larger in surface area than the threading itself.
But still, all bolts have threading of some length or the other. A bolt's threading works with the internal threading of a workpiece to join them. On the other hand, the bolt's threading is located on its outer surface.
Types of bolts
There are many different types of bolts provided by bolt manufacturers in Europe depending on the use case.Or the materials involved. Some of the more common types are:
• Anchor Bolt: This type of bolt is usually used in concrete or masonry for structural applications.
• Carriage Bolts: This type of bolt is used to fasten metal to wood. It has a squared undercut to the head. This undercut holds the head in place once it has been tightened.
• Elevator bolt: This type of bolt finds the most common application in conveyor belt systems. It has a flat, countersunk or plain head which similarly holds the bolt in place after tightening.
• Flange bolt: This type of bolt is known as a frame bolt. It uses a washer on the underside of the head, which works to distribute the load-bearing points.
• Hanger bolt: This type of bolt has two threaded ends. It does not have a head, instead, one of the ends contains a wooden screw.
• Huck bolt: A proprietary bolt that has the pin and collar swanged together using a special tool to form a permanent fixing.
• Hexagon bolt/ Tap bolt: These two types of bolts are very similar. A hexagon bolt has six sides and its threading begins halfway down the shank. Tap bolts, on the other hand, have a shank that is threaded the whole way.
• Lag bolt: This type of bolt is known as a lag screw. These are heavy-duty fasteners that can create their own thread in wood and other soft material when tightened.
• Machine bolt: This type of bolt is used to assemble metal components through pre-drilled holes and has a short shank.
• Plow bolt: This type of bolt is commonly used in construction tools and other devices because of its durability. It is characterised by its countersunk head and square shank neck.
• Square head bolt: As the name suggests, it has a four-sided head and a short shank. It is very similar otherwise to a machine bolt.
• Stud bolt: This type of bolt has hexagon nuts on both of the ends. Components are fastened between the two bolts in this type of bolt.
• Timber bolts: These types of bolts are meant to be used with larger timber components.
• U-bolt: these types of bolts are similar to staples. They are bent in the shape of a 'U' and have partial threading on both ends.
There are many kinds of bolts with various slight differences for different use cases. Bolts differ in the way of materials used too. However, nowadays, most bolts are made of steel and have various finishes. These finishes can be found with all the best bolt manufacturers in Europe. Some of these include hot dip galvanised, black phosphate zinc plated, bichormated, etc.
