A blowout preventer having a first elongated cavity extending along a first axis and a second elongated cavity extending perpendicular to and intersecting the first elongated cavity, a shear block provided in the first elongated cavity and configured to slide along the first axis, where the shear block has a frontal face facing the second elongated cavity and configured to slide towards the second elongated cavity; and a shear blade configured to be attached to the shear block and also configured to shear a tool provided in the second cavity when the shear block slides towards the tool. The frontal face of the shear block has at least a pin region configured to enter a tail region of the shear blade such that the pin region and the tail region form a dovetail joint or the shear block has the tail region and the shear block has the pin region.