SAE bolts are the fasteners most commonly used in automobile and motorcycle engines. They are also used in other applications such as furniture, industrial machinery and aerospace parts. These bolts are identified by their size, as well as a grade, which refers to the strength of the material. Bolts with higher grades are made of harder materials and have greater tensile strengths. They are more likely to hold up under the stress of heavy loads, such as vibration and external forces.
SAE stands for the Society of Automotive Engineers, and the organization set the standards for these fasteners. A bolt is a type of threaded fastener with an external male thread and a female countersink that allows the nut to grip the bolt head. These fasteners are usually made of metal, and they have a thread pattern that matches the threads on the nut to which they will be attached.
Most bolts have a hex head, which makes it easy to use an appropriately-sized wrench or socket on the head. Bolts with other types of heads are less common. A hex head has six sides, which means that it can accept a hex tool or socket with six points. It is also possible to find square-head and oval-head bolts, which require different tools to tighten and remove.
There are a number of SAE fastener standards that apply to bolts, screws and studs. For example, a screw must have a certain number of threads per inch to be considered an SAE bolt. A bolt with more than 24 threads per inch is called a coarse thread; while a bolt with fewer than 24 threads per inch is called
SAE bolts also have specific tensile strength requirements. These are determined by the hardness of the bolt’s material, as well as any testing requirements. For example, a SAE bolt may be tested for proof load or tensile strength, as well as to determine whether it is a satisfactory fastener for an application.
In addition to tensile and proof load requirements, there are specific hardness requirements for each bolt grade. These are often called “hardness properties” or something similar. These are important for determining the maximum amount of force that can be applied to a bolt without causing it to break.
Some bolts, such as those used in motors and other high-speed applications, are required to have a special coating that helps prevent corrosion. The coating can be a paint, powder coat or another layer of material that protects the bolt and helps it to last longer. In these cases, a bolt with this coating is often marked as a “special fastener” with an indicator symbol on the head. This is to make it easier for users to identify the bolt when they are working on a project. Other bolts are marked to indicate that they have been heat treated to improve their strength. This is usually done to increase their hardness, but it can also improve the durability of a bolt.