If you do an internet search for shingling hatchet, you'll get hundreds of pictures of lathing hatchets. Pretty senseless, but there it is. The narrow blade is designed for cutting laths. Shingles are wider, and since you don't want to have them split when you cut them with a hatchet, so is the blade of an actual shingling hatchet. A half hatchet will do, but a real shingling hatchet looks like this. (Along with the claw hatchet, the shingling hatchet was the first mass produced hatchet -- circa 1845)