Drills, specially constructed for "production" of square mortises.
Easiest production of joints.
Consists of two parts, a sharp chisel and a drill bit.
For use on mortises or drills.
The hollow square mortiser chisels are ideal for production of square mortises. The drill inside a square sleeve first drills a small round hole and the square sleeve then knocks out sharp edges around the hole. The drill is spindle driven whilst the sleeve is stationary. The corners are knocked out thanks to the stroke of special spikes, which drive themselves into the material.