UNF Bolts, Nuts and Washers

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.

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 'shoulder' or portion of the shank. A hex drive permits a greater torque load to be applied to the joint over most other drive types.

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 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.

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 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.

Philips Truss Head Machine Screws (UNF) has 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 Fine thread version. Phillips drive is x-shaped for installation with a Phillips screw driver.

UNF 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 which the screw diver is used to tighten the fixing. They are similar to a Pan head machine screw, but with greater side height. Height to diameter ratio is larger than a cheese head. Imperial Unified Fine thread version.

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.

Also known as an Allen 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.

Hexagon full nut to ASME B18.6.3. Typically fitted with a spanner or ratchet with socket. The most popular nut type, and used for decades on all types of assembly throughout the world.

Hexagon Machine Screw Nuts (UNF - Unified Fine Pitch) imported from the USA. These nuts generally have smaller internal diameters than the range available in standard hexagon nuts, so fit the smaller gauge sizes for Imperial screws. They also tend to be thinner or lower in height but have a larger outer diameter. These are specifically designed to be used in conjunction with other UNF screws or bolts. Often used in small electrical goods manufacturing, such as computers and hifi systems.

Prevailing torque type nut manufactured to IFI-100/107. Popularly employed Hexagon nut incorporating a nylon insert to help prevent loosening when fitted. Typically fitted with a spanner or ratchet with socket.

Prevailing torque nut, thin type. Popularly employed Hexagon nut incorporating a nylon insert to help prevent loosening when fitted. Typically fitted with a spanner or ratchet with socket.

Nut conforming to ASME B18.2.2. Also known as a half nut, thin nut, or jam nut. Typically fitted with a spanner or ratchet with socket, often used in pairs in a nut locking arrangement. A popular nut type, and used for decades on all types of assembly throughout the world.

A popular nut used in applications where aesthetics are important. Also known as an Acorn nut, these nuts are manufactured to ASME B18.2.2. These have a standard Unified Fine Thread Pitch (UNF). To be used in conjunction with same sized UNF screws and bolts.

An hexagon nut with incorporated flange. The flange offers protection for the bolted component where the driving tool may otherwise scratch it's surface. The flange also lessens the need to use a washer. This particular version has serrations on the base.

Popularly employed where frequent hand tightening and untightening of joints is required. To ASME B18.6.9.

Slotted or split beam type hexagon locking nut, of all metal construction with UNF thread form. Manufactured in the UK with the Aerotight trademark. Undersize threaded sections on top portion of nut mean that when tightened into position the undersize section is forced outward creating high friction and a more secure 'locked' fitment.

Flat washer manufactured to BS 3410 Table 3 Light Specification.

Also known as a penny or repair washer, this very popular type offers a large external diameter; it is therefore able to spread the load of the joint over a wider area. This is a useful feature when working with softer materials. Dimensions shown are approximate. Please note that hole clearances can be generous on these washers.

Flat washer to American SAE specifications, now part of the Unified Thread Standard. Washers with a smaller external diameter than that of an equivalent USS washer. Conforms to ASME B18.21.1-1999.

Flat washer to American USS specifications, now part of the Unified Thread Standard. Washers with an external diameter larger than that of an equivalent SAE washer, but smaller than a penny/fender washer. Conforms to ASME B18.21.1-1999.

Imperial Commercial Series washers imported from the USA. Similar thickness to the imperial Table 3 washers, also available on this site, but with a larger outer diameter. Available in 316 (A4) grade stainless steel, so ideal for marine use.

Flat washer with reduced outside diameter. Manufactured to NAS620, a standard specified by the Aerospace Industries Association of America.

Spring washer designed to help prevent loosening of bolted joints under vibration. This type has a rectangular section and is manufactured to ASME B18.21.1-1999.

A toothed or perforated washer usually employed in electrical connections such as battery terminals, but can also be used in assemblies to help prevent loosening. This variant includes teeth on the external diameter. Produced to ASME B18.21.1.

Military specification general purpose imperial sized round washers. Available in corrosion resistant A2 stainless steel and manufactured to US standard MS15795. Please note that these items can have large clearances to the bolt or stud: please refer to the data sheet for further information.

Nord-Lock washers, also known as wedge-locking washers, secure bolts with tension instead of friction. Working as a pair, these washers create a wedge-effect underneath the bolt head or nut so that the joint is prevented from loosening unintentionally. Nord-Lock washers are quick and easy to install and remove, and they are reusable. Supplied as a glued pair, they are appropriate for use in vehicles, for DIY and for watersport equipment. Most sizes are available in two external diameters: the smaller standard type listed here, and the larger SP type. Here you will find the specific imperial sizes; please refer to the data sheet and the metric section for other appropriate sizes.

Nord-Lock washers, also known as wedge-locking washers, secure bolts with tension instead of friction. Working as a pair, these washers create a wedge-effect underneath the bolt head or nut so that the joint is prevented from loosening unintentionally. Nord-Lock washers are quick and easy to install and remove, and they are reusable. Supplied as a glued pair, they are appropriate for use in vehicles, for DIY and for watersport equipment. Most sizes are available in two external diameters: the smaller standard type, and the larger SP type listed here. Here you will find the specific imperial sizes; please refer to the data sheet and the metric section for other appropriate sizes.