The toe knife is usually a full metal blade without handle, with a long straight cut (between 15 and 35 cm); there is also a model with handle and a short (approx. 7 cm) active part. The back of the toe knife is wide (5 mm), so that the farrier can hit it with his shoeing hammer. With the knife, the excess horn is cut away from the horse's hoof. Thus, the hoof is prepared for attaching a horseshoe.
As for shape, confusion is possible with a mason's tool to cut bricks to size.
See also horse rasp. [MOT]