25.08.2011 | In Focus

Splitting hairs

We are splitting hairs when it comes to maintaining the tolerances for Allen keys (hex key L-wrenches).

The permissible dimensional variations based on ISO standard for an Allen key of size 1.5 mm measures a mere 0.025 mm.

This means that the dimension of the key must fall between 1.475 and 1.500 mm.

A human hair measures between 0.04 and 0.1 mm.

The image shows the relationship between the permissible dimensions for an Allen key size 1.5 mm and an average human hair with a thickness of 0.07 mm.

Even for an Allen key of size 10 mm, the permissible deviations are less than the width of a hair.

Our tools safely fit into the screws without any major play. We guarantee that the tolerances are maintained from the smallest to the largest Allen key.


For the smallest dimensions of 0.71,  0.89 and 1.27 mm, the permissible deviations are so small that no nickel and chromium layers can be applied. For this reason, these tools are not delivered in chrome-plated design, but in black-finished design.

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