An arbor for a hole saw. The arbor includes an arbor stem having at least one arm with a threaded portion configured to engage the hole saw. The arbor further includes an actuator rotatable to move the at least one arm and a body mounted to the actuator. The body has a channel that receives the at least one arm. Moreover, the arbor includes at least one magnet positioned within the at least one arm.

This invention provides the means for construction crews to easily drill through multiple beams or soffits with the use of a hole saw that is coupled to a first drive cup using a coupling arbor. The first drive cup is attached to a first end of an extension tube and is secured using self-tapping screws. A second drive cup is attached to a second end of the extension tube with self-tapping screws where a drive coupling arbor provides a hexagonal shank that is attached to a drive device, such as a hammer drill or standard drill. When activated the rotational motion allows the hole saw to cut through the beams or soffits. A pilot bit is provided to guide the hole saw into the beams or soffits when in use.

A hole saw connecting mechanism, including a rotary shaft assembly and a hole-opening assembly; the rotary shaft assembly has a drill bit limiting sleeve and a limiting mechanism; the hole-opening assembly has a quick connecting head, a pilot drill bit, and a cylindrical hole saw; the limiting mechanism has a limiting steel ball and a sliding sleeve. A first limiting hole penetrates through the drill bit limiting sleeve; the limiting steel ball is in the first limiting hole; the quick connecting head has a first positioning groove to limit the limiting steel ball. The sliding sleeve has circular sidewalls of different diameters to cooperate with the limiting steel ball to achieve locked and unlocked states of the quick connecting head with respect to the drill bit limiting sleeve. The pilot drill bit is mounted to the quick connecting head or the drill bit limiting sleeve through a collar assembly.

A hole cutting accessory for a power-driven tool may include an arbor that provides for quick release of an annular saw blade component of the accessory, and for quick release of a pilot drill bit component of the accessory. The quick release of the annular saw blade component from the arbor may be accomplished separately from the quick release of the pilot drill bit component from the arbor.