Hex key (Allen key)
Llave hexagonal (llave Allen)
- Date
- 1910 · confidence medium
- Place
- Hartford, Connecticut, United States
- Credited to
- William G. Allen
- Field
- Tools
⚠️ Disputed: the sources disagree.
What it is
An L-shaped hexagonal-section key that fits the socket of cap screws and is very cheap to manufacture. Allen Manufacturing Company marketed it in 1910 in Hartford.
The hexagonal-socket screw had precedents in the Bauer patent and in other British and US patents of the early 20th century; the name 'Allen' comes from the 1910 trademark.
What it led to
- socket-head screws in compact machinery
- flat-pack furniture and bicycle assembly
- hex and ball-end key sets