Instead of using a roofer's hammer and slater's stake, slates can also be cut to size with these slate shears. These are scissors with a flat lower jaw that slopes downwards and in which there is a rectangular recess in which the upper jaw fits. The slate is placed on the lower jaw and when closing the scissors, a piece of the slate is cut off. In this way, one can continue to cut along the same line to remove a complete piece of the slate. Often there is a protrusion on one of the arms that prevents the hand from sliding forward when cutting.
There are also fixed models with a sharp protrusion that can be hammered into the roof boarding. [MOT]