1For low cost sheet metal holemaking. Blaircutters provide fast, accurate, burr-free holes in materials up to 3/16" thick. Light-duty Blaircutters are annular cutting tools that cut around the edge of the hole and eject the center as a slug. Because they're hollow, there's no dead zone as with twist drills. Unlike hole saws, that rip and tear through the material, they quickly give you a quality, virtually burr-free hole. Blaircutters are available in seven sizes for 1/4" and larger drill chucks. Spring loaded pilot "pops" the slug from the cutter.