Abstract: A flanged irregular bushing is fitted through a corresponding irregular hole in the base of a conventional hole saw and supports a cylindrical shank which extends from the back of the hole saw. Either the bushing or the shank is internally threaded with right hand leading threads. A collar is free to reciprocate on the shank and has pins projecting through corresponding holes through the base of the hole saw into the cup of the saw. The distance by which the pins extend into the cup of the hole saw depends upon the location of the collar on the shank. When the collar is positioned away from the base of the hole saw the pins extend only a short distance into the cup of the saw, permitting the mandrel to be threaded deeply into the saw with the fingers on the end of the saw close to the saw base.

Abstract: A device is disclosed for driving conventional hole saws and for extruding sawed material from within said saws after sawing. An internally right hand threaded shank is attached to the outer base end of a conventional hole saw. A cooperating mandrel is threaded into the shank from within the hole saw. The end of the mandrel remaining in the hole saw forms wing-like projections which spiral into the hole saw as the mandrel is threaded into the shank. A sleeve freely mounted on the shank contains pins which protrude into the saw through complimentary holes provided in the base of the conventional hole saw to obstruct the spiral motion of the mandrel projections to transfer torque from the mandrel to the saw for sawing, and the sleeve is moved away from the hole saw on the shank, withdrawing the pins from within the saw to free the mandrel to thread out through the saw to extrude sawed contents therefrom.