Abstract: An improved hole saw is disclosed. A mandrel of the hole saw forms an elongated threaded body. The mandrel, at a first end forms a shank adapted to be secured in the chuck of a hand power drill or drill press. The second end of the mandrel forms an enlarged, radially extended, circular flange having a recessed axially aligned hole formed therein. The shank end of, for example, a quarter inch pilot-hole drill is secured in the flanged end of the mandrel by one or more set screws. The mandrel is inserted, shank end first, into the open serrated cutting end of a cylindrically shaped hole saw. The threaded shank end of the mandrel is screwed into a threaded base of the hole saw, the radially extended flange of the mandrel being mated to and tightened against the inside base end of the hole saw.

Abstract: A device for removing waste plugs from hole saws comprising a plug member positioned internally of a hole saw and retained therein by means of screws or other projections which extend outwardly through cleanout slots of the hole saw. The projections may be joined through an external annular ring which encircles the hole saw. The ring may be grasped and forced downwardly causing the plug member to eject a waste plug from the hole saw. A spring may be positioned between a mandrel of the hole saw and the plug member in order to normally bias a plug member downwardly to assist its positioning and ejectment of a waste plug.

Abstract: A pilot pin-locking means for a drilling machine including a drilling tool, a hollow shaft for supporting the drilling tool and provided with a lubricating means, a bearing means mounted on the drilling machine, the shaft being supported by the bearing means for vertical movement and rotation about an axis, further including a pilot pin inserted through the center of the drilling tool for vertical movement.The hollow shaft receives an engaging means that engages the pilot pin under the resilient action of a spring in a vertically movable manner. The engaging means is detachably locked to and biased against the inner face of the hollow shaft.

Abstract: A drilling machine including a spindle and an elevating hollow shaft rotatable in unison with the spindle. An annular cutter is mounted in axial alignment with the hollow shaft and an elevating center drill is mounted in axial alignment with the annular cutter. The drill is movable to descend relative to the annular cutter to initiate the formation of a center hole in a workpiece prior to drilling. The drilling machine further includes a cylindrical member vertically movable and rotatably supported within a holder with the elevating hollow shaft being vertically movable and rotatably supported within the cylindrical member.

Abstract: An arbor for a rotary cutting tool which includes an elongated cylindrical shank that has an axial bore formed therethrough. The upper end of the shank is adapted to be attached to the drive spindle of an electric motor. The arbor shaft is slidably mounted in a carrier sleeve which is rotatable with the arbor shank which is retained against axial movement by a mounting means. An annular cutter is attached to the lower end of the arbor shank and a pilot ejector member is slidably mounted therein. The pilot ejector member is retained in the normal at rest position by a spring which has its upper end mounted in a bore in a piston that is attached to the carrier sleeve. The lower end of the spring engages a plunger member which maintains the pilot ejector member in its initial and other operative positions.

Abstract: A method and tool for trepanning holes in a composite of materials having different strength and elastic characteristics. The method provides for simultaneous point and surface cutting which occurs at the inner and outer circumferential surfaces of an annular hold being formed. The trepanning tool includes a cylindrical side wall with portions removed at one end to form a plurality of cutting elements or teeth. Each tooth includes a cutting single end point and associated cutting edges, there being inwardly and outwardly directed teeth.

Abstract: An apparatus for forming a hole in a bone is provided, which comprises a body, a drill bit rotatable with respect to the body, and, in order to locate the drill, a mandrel coaxial with the drill bit, slidably projectable through the drill bit and biased to an extended position.

Abstract: A rotatable shell cutter member for cutting a hole in large diameter and thick wall plastic pipe. The shell cutter member is rotated and advanced with a positive predetermined lead against the plastic pipe and it first forms a hole in the plastic pipe by cutting and retaining a coupon therefrom and it further progressively enlarges the hole to a diameter equal to or slightly greater than the overall outside diameter of the shell cutter member. The chips initially cut from the plastic pipe in cutting the coupon are discharged upwardly and inwardly of the shell cutter member above the coupon being cut and, when the shell cutter member with its cutting edge in constant cutting engagement with the pipe begins cutting a continuous chip cut, it is also discharged upwardly and inwardly of the shell cutter member.

Abstract: Disclosed is a core drill for cutting cylindrical sections from stone, glass, shell and other hard materials, while simultaneously drilling a centered hole in each cylindrical section. The drill comprises an abrasive tipped hollow cylindrical core drill and a drill bit positioned centrally within the core barrel.