Leather workers such as the saddler use this hand tool to cut decorative shapes from the leather.
It is a steel chisel (approx. 10-15 cm long) without handle with a serrated or corrugated blade that can be flat and flared, semicircular or circular (cf. the punch).
The cutting chisel is placed on the leather and hit with a hammer; the desired shape is cut into the leather. [MOT]