SAE bolts are a type of fastener used in many different types of projects. They are standardized by a number of different standards that dictate material, performance and test requirements.
Bolt strength is rated based on the amount of stress and pressure that can be applied before the bolt fails. Most standard bolts are made of carbon or alloy steel, with varying proof and tensile strengths.
Grades
Bolts are important in the engineering world because they literally hold things together. That is why it is crucial to get the right bolt for any job, especially if that job requires high strength or loads of pressure.
Several different standards organizations have come up with systems that allow you to determine the strength of a bolt or fastener by looking at its yield strength and proof load. The yield strength is the maximum load a fastener can withstand before it breaks. The proof load is the axial tensile stress a bolt can withstand without permanent deformation.
The Society of Automotive Engineers has two general kinds of bolt grades. The first is grade 2, which has a low to medium carbon steel with quenching and tempering. The second is grade 8, which is made of a higher carbon alloy and is heat treated to give it a minimum tensile strength of 150,000 psi. You can recognize grade 8 bolts by the six raised hash marks on their hex heads.
Materials
Bolts are one of the most important elements used in many different industries. This is why they have to be made from strong and durable materials. They are used to fasten many parts together and so they need to be able to withstand high stresses.
The most common material for bolts is steel, which can be low, medium or alloy. There are also other types of metals that can be used, but these are less common than steel. Bolts are rated by their strength and this is determined by the amount of pressure that can be applied before they break. This is known as the bolt shear or tensile strength.
Grade 2 bolts, which are made from low or medium carbon steel, have a lower tensile strength and are generally used for non-critical applications. While Grade 5 bolts, which are made from quenched and tempered medium carbon steel, have a higher tensile strength and are often used in critical areas such as vehicle suspensions.
Thread Pitch
Despite the fact that the majority of hardware in use today is made to metric standards, many older fasteners still bear SAE markings. SAE stands for Society of Automotive Engineers, which maintains standards in the automotive and aerospace industries. Special markings on the head of an SAE bolt indicate its tensile strength, with higher numbers indicating greater strength.
SAE bolts also have a thread pitch, which determines how far apart each thread is. A higher number indicates a coarser thread, while a lower one means a finer one. For example, a 1/4 “- 20 bolt has a coarse thread while a 1/4 “-24 bolt has a fine thread.
These sizes are fractional inch based, so when you buy tools at the hardware store it’s important to read their packaging to know whether you’re buying SAE or metric. You don’t want to be stuck with a socket that fits a size you can’t use. A quick glance at the label will tell you what size you’re purchasing.
Sockets
A set of SAE and metric sockets is a must-have for any tool box. These durable tools are used to remove damaged bolts with rounded or rusted heads that can’t be turned with a wrench or open-end or box-end socket. They’re also useful for removing or loosening fasteners that are stuck or frozen in place.
These high-quality, professional-grade tools are made of chrome vanadium steel and feature SUPERTORQUE lobular openings for greater turning power without deforming the head of the fastener. They’re packed in rugged, high-density polyethylene cases and come with a ratchet with 7 locking positions.
Many people make the mistake of using SAE sockets on metric fasteners or vice versa. Although these two sizes have similar crossovers, it’s best to use the correct socket for your particular application to avoid stripping a bolt. Also, the tolerances of these two systems are different, so it’s important to get a full set of both types of sockets.