Hex keys, also called Allen keys, are L-shaped or handled tools that turn screws and bolts with a hexagonal socket. They suit DIY users, cyclists, furniture assemblers and workshop technicians. The main types are single L-keys, folding sets, T-handle keys and ball-end keys, in metric and imperial sizes.
No models are listed in this category at the moment, so the advice below applies to hex keys in general.
How to choose hex keys
Size system. Metric keys are measured in millimetres (commonly 1.5 mm to 10 mm) and imperial keys in fractions of an inch. The two are close in places but not interchangeable, and a key that is slightly too small will round off the socket. Check the screws on your furniture, bike or machine before you buy.
Key type. A standard L-key is cheap, light and fits in a drawer. A T-handle gives better grip and speed for repeated work, while a folding set keeps every size in one holder for the toolbox or saddlebag. Ball-end keys let you turn a screw at an angle, though they transmit less torque than the straight end.
Material and finish. Most good hex keys are made from hardened alloy steel such as chrome vanadium or S2, which resists twisting and rounding. A plated or black oxide finish helps against rust. Very soft, unbranded keys can bend or strip under load, which also damages the screw.
Length and set contents. Long-arm keys reach deep or recessed screws and give more leverage, while short-arm keys suit tight spaces. A set that covers the sizes you actually use is better value than a large set with many sizes you never touch. If you work on one product type, such as bicycles, check which sizes it needs.
Hex key types to look for
- L-keys: the classic single-piece design, usually sold individually or in sets, with a short and a long arm for different reach and leverage.
- Folding sets: several keys hinged into one handle, handy for quick adjustments and for carrying in a tool bag.
- T-handle keys: a fixed handle gives a comfortable grip and quicker turning, which helps with long assembly jobs.
- Ball-end keys: a rounded tip allows an angled approach to the screw, useful where access is awkward.
Specific brands will appear here once models are added to the category.
Hex keys FAQ
What is the difference between a hex key and an Allen key?
There is no practical difference. Allen is a trade name that became the everyday word for a hex key in many countries. Both describe a tool with a hexagonal cross-section that fits a hex socket screw.
How do I know which hex key size I need?
Try the key in the screw socket: it should slide in with almost no play. If it wobbles, it is too small, and if it will not enter, it is too large or from the wrong system. Check whether the product is metric or imperial, as many items sold in South Africa use metric sizes.
Are ball-end hex keys as strong as standard ones?
No, the ball end is designed for access rather than force. Use the ball end to start or lightly turn a screw at an angle. Switch to the straight end for final tightening or for loosening a tight screw.
What is a good hex key set for home use?
A metric set that covers roughly 2 mm to 10 mm handles most flat-pack furniture, bicycles and household fittings. Choose alloy steel keys with a rust-resistant finish and a case or holder that keeps the sizes organised. Add an imperial set only if you own equipment that uses inch sizes.
