UNC Bolts

The most common type of fastener, a hex head bolt is designed to be tightened with a standard spanner or ratchet and socket. Popularly used in all assemblies, a standard hex bolt is a staple across the world. Manufactured to ASME B18.2.1, and includes an unthreaded section of the shaft. A hex drive permits a greater torque load to be applied to the joint over most other drive types.

Commonly referred to as a setscrew and longer versions are referred to in the United States as a tap bolt. A standard spanner or ratchet is typically used to fit this product. Used for decades on all types of assembly throughout the world. The hex drive allows a higher torque to be applied. Produced to ASME B18.2.1.

Also known as an Allen screw or Allen bolt, or simply a cap screw, socket head cap screws are a more modern alternative standard machine fastener to the standard hexagon headed bolt or setscrew, as found on much modern machinery. A hex key (otherwise known as an Allen key) is required to fit these fasteners. Conforming to ASME/ANSI B18.3, the contact surfaces of this screw or bolt are protected from external damage. Generally manufactured with a partial thread beyond a certain length and nominal diameter combination, but occasionally some stock may include a fully threaded shank at the same combination.

A popular and attractive socket head screw, typically used where aesthetics are important, or where a lower profile domed finish is required. The hex drive is generally smaller than other hex driven ranges and thus the ultimate tightening torque is reduced. Manufactured to ASME/ANSI B18.3, and always fully threaded.

A countersunk headed screw conforming with ASME/ANSI B18.3, requiring a hex key (otherwise known as an Allen key) to fit. The countersunk head is typically used in conjunction with a countersunk hole providing a flush, snag free fit. Generally manufactured with a full thread, though occasionally some stock may include a partially threaded shank.

Also known as a set screw, these headless types of screws have many uses. This particular type has a hex socket drive, and a depression called a 'cup' on the opposite end, and conforms to ASME/ANSI B18.3.

Flexible usage threaded bar or threaded rod to ASME B18.31.3.

A Machine screw with a phillips drive, designed to be tightened with a screwdriver. Typically found on consumer electronics and other small machinery where high torque fasteners are not necessary. Conforms with ASME B18.6.3.

A popular machine screw with a phillips drive. The countersunk head is typically used in conjunction with a countersunk hole providing a flush, snag free fit. These items are always fully threaded. Conforms to ASME B18.6.3. Typically found on consumer electronics and other small machinery where high torque fasteners are not necessary.

A countersunk headed screw incorporating a slightly raised head which gives it an attractive finish when fitted. Includes a phillips cross recess for driving in. Manufactured to ANSI/ASME B18.6.3.

UNC Phillips Fillister machine screws have a large cylindrical head, with a slightly convex top surface. Fillister head screws are the preferred head type for counterbored holes and can also be used for protecting a surface by raising the level by which the tool is used to tighten the fixing. They are similar to a Pan head machine screw, but with a greater head height. Height to diameter ratio is also larger than a cheese head. Imperial Unified Coarse thread version.

Philips Truss Head Machine Screws (UNC) have a wide and shallow domed shape, which can negate the use of a washer. The head shape also gives a larger contact area with the surface, which means a snag free fitment and helps guard against tampering. For use either in a pre-tapped hole or nut assembly. Ideal for sheet metal projects and applications where there is minimal clearance, such as sliding supports in draws and cabinets. Imperial Unified Coarse thread version. Phillips drive is x-shaped for installation with a Phillips screw driver.

Socket shoulder screw with a UNC imperial coarse thread. They are also known as shoulder bolts, precision shoulder screw and in the US, stripper bolts. The main dimensions are for the diameter and total length required under the head. Shoulder screws have an undercut portion between the thread and shoulder, allowing a close fit. They are used in a wide range of punch and die operations and as shafts, pivots, guides, pins, linkages and trunion mountings. Please note that the nominal diameter here refers to the shoulder diameter, except where shown otherwise.

Hexagon headed bolt with a flange. Also known as a washer bolt. The wider surface area beneath the head spreads the clamping pressure and negates the need for a washer. These UNC hex head flange bolts are serrated. The serrations are anti-rotational and bite into the material which they are connecting to secure the fixing.