Inventors:
Bobby J. Collard - Garland TX
International Classification:
B23B 4100
Abstract:
A shaft sized to fit conventional hole saw mandrels has two set screw flats and a retaining head. A cylindrical roller is mounted on the shaft against the retaining head, and a cylindrical spacer is mounted by set screws on the shaft above the roller. The roller is sized to fit the diameter of holes typically desired to be enlarged. The shaft, roller and spacer assembly is mounted in the mandrel of a conventional hole saw using the second set screw flat so that the roller extends beyond the cutting edge of the saw. The roller is inserted into the existing hole and guides the hole saw as the hole saw is turned by a drill or other means. In an alternate embodiment, the roller has side flats, allowing the device to enlarge oblong holes having parallel sides.