Particularly valuable for retrofitting door locks, installing piping in an old house, or simply correcting mistakes, this clever attachment replaces the mandrel's pilot bit and couples two sizes of hole saw (with a minimum 3/16" diameter difference). The smaller hole saw acts as the pilot by following the existing hole, while the larger saw cuts the new hole.Compatible with our bimetal hole saws and mandrels, it has a 1/4" diameter shank, and its stepped mandrel is threaded to accept saws with 1/2" and 5/8" diameter mounting holes.Made in USA.
