The blades of the entire range of allen keys are forged from chrome vanadium steel which has undergone a high frequency heat treatment in order to achieve a hardness of between 160 and 180kg/mm². The quality of this steel allows a reduction in the thickness of the resulting key, meaning that, after the insulation process, the Clydesdale / Sibille range of keys is comparable in thickness to other non-insulated keys of the same usable size. The tightening torques achieved by Clydesdale / Sibille keys are greater by approx. 60% than those specified by the nut and bolt industries by their standards worldwide.

Metric Sizes