A support assembly for a core drill which utilizes an improved high strength spoked reinforcer. The reinforcer may be removably mounted a core drill tube by fasteners. A drive connection is removably mounted and centrally located on an outer disc of a pair of discs. The drive connection is adapted to connect with a drive shaft to cause rotation of the tube. The assembly can also include a split in the disc when the high strength spoked reinforcer is not welded thereto, thereby providing a means of water control. The high strength spoked reinforcer can be a separate piece that is bolted to the disc or can be integrally formed as one piece therewith.

A hole cutter has a cylindrical blade body including a cutting edge and one or more axially-elongated apertures formed within a side wall of the blade body. The axially-elongated aperture is configured to receive a lever, such as a screwdriver, therethrough. Each axially-elongated aperture includes a first fulcrum axially spaced adjacent to the cutting edge, a second fulcrum axially spaced further away from the cutting edge than the first fulcrum, and optionally a third fulcrum axially spaced between the first and second fulcrums. A lever, such as a screwdriver, can be inserted into the aperture and placed against each of the fulcrums to lever slugs out of the interior of the blade body.

A hole cutter has a substantially cylindrical blade body defining a blade body circumference, a cutting edge formed on one end of the blade body, and an axially-elongated slot formed through the substantially cylindrical blade body. The axially-elongated slot is configured to receive chips flowing from the cutting edge within the interior of the blade body and (i) into the slot and/or (ii) through the slot, to prevent the collection of such chips within the interior of the blade body and/or at an interface between the blade body and the work piece. The axially-elongated slot defines a first end adjacent to the cutting edge, a second end axially spaced further from the cutting edge, and a slot area. The hole cutter further defines a total slot area to blade body circumference ratio within the range of about 0.1 to about 0.3 depending on the size of the hole cutter.

A hole saw is movable about a rotational axis in a cutting direction to cut into a workpiece. The hole saw includes a cylindrical body with a sidewall having a first end and a second end opposite the first end, a gullet formed in the sidewall between a leading surface, a trailing surface, and a bottom surface of the sidewall, and a support aperture formed in the sidewall. The gullet extends through the first end of the body. The support aperture is entirely surrounded by the sidewall. A majority of the support aperture circumferentially overlaps with the gullet. At least a portion of the support aperture is positioned closer than the bottom surface of the sidewall to the second end. The hole saw includes a cutting tooth coupled to the first end of the sidewall adjacent the gullet and an end cap coupled to the second end of the sidewall.

A pilot pin assembly is slidably receivable within a tool bit of a drill press. The pilot pin assembly includes a first pin defining an interior cavity, and a second pin at least partially received within the interior cavity of the first pin. A spring is positioned within the interior cavity for biasing the second pin toward an extended position relative to the first pin.

A hole cutter has a substantially cylindrical blade body defining a blade body circumference, a cutting edge formed on one end of the blade body, and an axially-elongated slot formed through the substantially cylindrical blade body. The axially-elongated slot is configured to receive chips flowing from the cutting edge within the interior of the blade body and (i) into the slot and/or (ii) through the slot, to prevent the collection of such chips within the interior of the blade body and/or at an interface between the blade body and the work piece. The axially-elongated slot defines a first end adjacent to the cutting edge, a second end axially spaced further from the cutting edge, and a slot area. The hole cutter further defines a total slot area to blade body circumference ratio within the range of about 0.1 to about 0.3 depending on the size of the hole cutter.

A drill bit has a cutting portion having an annular portion, where the annular portion has a first end on which is disposed a cutting element and a second end that includes an outer insertion element and a stop shoulder. The drill bit has a drill shaft portion having a cylindrical drill shaft, where the drill shaft has an inner insertion element with an end face on a side of the drill shaft facing the cutting portion. The outer insertion element and the inner insertion element together form a plug connection in an insertion direction that is parallel to the axis of rotation and the insertion elements are connectable to each other via a pin element that is movable into a slot-shaped recess. The pin element is attached to an outside of the inner insertion element and the outer insertion element has the slot-shaped recess.

A hole saw alignment guide for enlarging a hole in an object to provide a larger diameter hole in the object. The hole saw guide includes a first cylindrical part having a first end adapted to the size of, and adapted to be inserted into, the hole that is to be enlarged. The hole saw guide also has a second cylindrical part integral with the second end of the first cylindrical part. The hole saw guide is adapted to receive over the outer surface of the first cylindrical part a toothed end of a hole saw sized to provide the larger diameter hole. The second cylindrical part is adapted to extend into an arbor of the hole saw and to be secured to the arbor for rotation with the hole saw. The arbor of the hole saw is adapted to be received in a drill chuck.

A hole cutter has a cylindrical blade body including a cutting edge and one or more axially-elongated apertures formed within a side wall of the blade body. The axially-elongated aperture is configured to receive a lever, such as a screwdriver, therethrough. Each axially-elongated aperture includes a first fulcrum axially spaced adjacent to the cutting edge, a second fulcrum axially spaced further away from the cutting edge than the first fulcrum, and optionally a third fulcrum axially spaced between the first and second fulcrums. A lever, such as a screwdriver, can be inserted into the aperture and placed against each of the fulcrums to lever slugs out of the interior of the blade body.

The invention relates to a core drill with an end portion (3) and a drill bit portion (1-2). The end portion and the drill bit portion are joinable in a watertight fashion with a sealing element (11). The sealing element (11) is provided in a space between the end portion and the drill bit portion, such that it is being compressed in a sealing fashion when the end portion and the drill bit portion are joined. The end portion and the drill bit portion are locked together with a joining element (8, 10) which achieves this locking effect when moves in the radial direction of the core drill. When the joining element moves in this direction, the end portion and the drill bit portion move towards each other. Thus the sealing element is being compressed while concurrently the end portion and the drill bit portion are joined together. This is further achieved without the joining element having to extend in the axial direction of the core drill. Typically, the joining element (8, 10) is constituted by a set screw.