It is a type of cap screw with a hexagonal recessed drive and specifically designed to test the amount of tensile (stretching) stress a material can withstand before breaking or failing and for die applications. They also are usually made from stronger alloy steel vs. other screws, but this depends on the grade and the manufacturer. They are fastened using a socket wrench and have different types of head designs which includes a cylindrical head, a button head and flat head, the latter designed to be seated into countersunk holes. Amongst the different types of screws, the Socket head cap screws are commonly utilized in the industry because of its safety, reliability and economy.
They are used for machine assembly, especially for removable parts, and for applications with limited spaces since they take up less space and don't require side room for wrenches. Another factor is that compared to ordinary screws, less socket screws can achieve the same clamping force in a joint. As fewer screws are used for a given job, fewer holes are required to be drilled, there is also considerable weight reduction. However, they also have three disadvantages. First, they have small heads. If they are to be loaded in tension, the limited bearing area under the head will prevent tightening the bolt sufficiently to take full advantage of the strength of the alloy. Second, they are manufactured with very long thread, which is the ridge wrapped around a cylinder or cone in the form of a helix. And third, the heads are case hardened and are therefore difficult to drill for safety wire.
Since there are different types of socket head cap screws nowadays, you have to choose what size and design your going to use. Because of this, you need to be careful in purchasing the items you need. You have to keep in mind that different types of screws also have different purposes. In other words, certain screws are made for certain types of machines, tools, or projects. A range of choices for special use applications are:
• High temperature
• Corrosive environments
• Maximum tensile strength critical
• Cleanliness required
