Allen Key Sets.

What are Allen Key Sets?

An Allen key set is a graded group of L-shaped hexagonal bars, also listed as a hex key set, a hexagon socket key wrench set or an Allen wrench key set.

Each key is a length of hexagonal steel bar bent at ninety degrees to give a long arm and a short arm, with the set graded in ascending socket size. Covering a defined size range in one purchase means every hexagon socket fastener gets a dedicated Allen key size, which is what keeps sockets intact.

Socket screws dominate applications where fasteners are tightened to a specification, then repeatedly removed, putting graded key sets into machine building, robotics, automotive assembly and general maintenance. The format survives because it has no handle, pivot or mechanism to fail when compared to a screwdriver set of the same type, making them a simple, reliable tool to reach for while being able to physically access fasteners in hard-to-reach assemblies.

How Allen Key Sets Work

The six flats of a hex key engage precisely with the fastener's socket, distributing rotational force across the entire internal face rather than concentrating it on a single slot or cruciform. That distributed contact lets a small hex key transmit torque which would strip slotted head screws of the same size. 

The L-shape then provides two distinct working modes; inserting the short arm applies maximum leverage through the long arm for breaking seized fixings loose or applying final torque. In confined clearances, the short arm's low-profile engagement becomes critical, which makes minimum short-arm length as important as the tool's overall reach.

A maintenance engineer stripping an aluminium machine guard meets cap head screws in several sizes, many of them recessed into deep countersinks. A graded set ensures the correct size is immediately to hand without manual gauging, while the extended long arm reaches into narrow counterbores that a standard socket and ratchet simply could not reach.

What Materials Allen Key Sets Are Made From

Accu's Allen key sets are manufactured from engineering-grade materials, selected for the balance of hardness and toughness a hex drive demands:

• Steel / Plastic - TP: Hardened tool steel transmits high torque through a small cross-section without deforming the drive corners, with a thermoplastic holder keeping the set graded by size.
• Stainless Steel / Plastic - TP: The same working geometry in a corrosion-resistant alloy, for damp, outdoor or washdown environments where plain steel would rust.

What Size and Type Allen Key Sets Are Available

Accu's range of Allen key sets is available in a variety of socket sizes, arm lengths and finishes to accommodate differing access and torque requirements:

• Socket Size: 1.5 mm to 10 mm.
• Long Arm Length: 50 mm to 224 mm.
• Minimum Short Arm Length: 14 mm to 42 mm.
• Finish: BlackLaser and Natural.

Socket sizes step through 1.5, 2, 2.5, 3, 4, 5, 6, 8 and 10 mm, taking in everything from small instrument fixings up to structural cap head screws. 

Compact configurations keep long arms under 125 mm where overall tool length is constrained, while longer configurations extend to 224 mm for deeply recessed fasteners. 

BlackLaser gives a dark low-reflectance surface with added corrosion and wear protection, while Natural leaves the base material exposed, the standard option on stainless steel sets.

FAQs

Q: Why is it called Allen key set?

A: The name comes from the Allen Manufacturing Company of Hartford, Connecticut, which trademarked "Allen" for its hexagon socket screws and matching wrenches in the early twentieth century. The term outgrew the manufacturer and became the everyday name for the tool type. Hex key and hexagon socket key wrench remain the correct generic terms.

Q: What is a good quality Allen key set?

A: Judge a set on four points. Hexagon profile tolerance comes first, because play inside the socket is what rounds the corners of tool and fastener alike. Then steel grade and heat treatment, balancing hardness against brittle fracture. Then size coverage, since a skipped size means a replacement set. Then corrosion protection matched to the environment.

Q: What is the difference between an Allen key and a hex key?

A: There is no difference. Both name the same L-shaped hexagonal bar that drives an internal hexagon socket. Allen began as a trademark of the Allen Manufacturing Company before entering general use, while hex key and hexagon socket key wrench are the generic engineering terms. Accu lists the range under both names.

Q: How do you stop an Allen key rounding the socket?

A: Seat the key fully before applying force, since partial engagement concentrates load on the top of the socket flats. Use the correct size rather than the nearest fit, as play is what rounds corners. Replace keys showing worn or shiny corners, because a deformed key damages every fastener it touches afterwards.

Bespoke Allen Key Sets Manufacture.

High precision, bespoke manufacture of Allen Key Sets to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.