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304 Stainless Steel 316 Stainless Steel
Socket Set Screw Kits Socket Set Screws - Metric Sizes

Socket Set Screws

Set or "Grub" Screws with an Internal Hex Allen Drive

Set Screws are blind (headless) fasteners with an internal hex drive. It is this drive style that classifies Stainless Steel Screws in this selection as Socket Set Screws, which are driven by a hex bit or Allen wrench. Set Screws are used in a tapped hole, and tightened to hold an exterior object in place within or against another object, via friction between the point or end of the screw and the material that is being fastened.

Set Screws, also known as grub screws, are also often used in applications where a flush installation and the look of the final assembly are important, such as furniture assembly. Socket Set Screws are headless, which means that they will run flush with the installation surface. They are often plugged after installation for a hidden fastener look. These qualities are what make socket set screws commonly used in applications where a flat surface is important, such as handles, grips, surfboard fins, and furniture or machine assembly. Because a flush surface is important on complex machines, Set Screws are also commonly used in gears, pulleys, and wheel in machines with moving parts.

A stainless steel set screw is a type of screw generally used to secure an object within or against another object. The most common examples are securing a pulley or gear to a shaft. Set screws are most often headless (also called blind), meaning that the screw is fully threaded and has no head projecting past the major diameter of the screw thread. A blind set screw (known in the UK as a grub screw, quite possibly from its figurative resemblance to a soil-dwelling grub) is almost always driven with an internal-wrenching drive, such as a hex socket (Allen) socket The set screw passes through a threaded hole in the outer object and is tightened against the inner object to prevent it from moving relative to the outer object. It exerts compression or clamping force through the bottom tip that projects through the hole.

An example application is when a set screw is screwed into a pulley hub so that its end-point bears firmly against the shaft. The fastening action is by friction between the screw and the shaft, often (but not always) with some amount of elastic or plastic deformation of one or both. These fasteners are also very popular in gun builds.

304 Stainless Steel

(18% Chrome, 8% Nickel, .08% Maximum Carbon) 18-8 Stainless refers to 300 series stainless steel. 303 and 304 Stainless are the most commonly listed grades, the standard grade for stainless steel fasteners. They are corrosion-resistant and durable. They are often used in marine applications in freshwater environments, but will not work as effectively in a salt water environment as 316 stainless. Stainless alloy resists oxidizing and rusting, however it can tarnish over time.

316 Stainless Steel

(16%-18% Chrome, 10%-14% Nickel, .08% Maximum Carbon, 2.00% Maximum Molybdenum) This grade of stainless steel is used and recommended for applications in severe, harsh or marine environments. Its corrosion resistance is greater than 18-8 stainless, which is why we recommend using 316 stainless steel fasteners for salt water application. It is important to remember that even the salt in the air near a body of salt water can do damage to dry applications, so 316 is the material of choice. Common applications of 316 stainless steel fasteners include use on boats, docks, piers, and pools.