A micro-reinforced concentric twist drill. Concentric drilling and micro-reinforcing technologies are applied to cutting faces of the twist drill, and upright micro-reinforced center drills are symmetrically arranged on spiral cutting surfaces on two sides of an axial central area, and extend to the rear cutting surface and form drill center hole cutters in a protruding manner; a micro-reinforced central cutting face is arranged on the inner side of each micro-reinforced center drill in a protruding manner, and the micro-reinforced central cutting face extends to the axial front and intersects with the rear cutting surface to form a micro-reinforced central drilling edge of the micro-reinforced concentric twist drill; and/or upright micro-reinforced reamers are symmetrically arranged on central areas of the spiral cutting surfaces on two sides of the axial center in an integral manner; a protruding reaming cutting face is formed on the inner side of each micro-reinforced reamer.

A cutting tool including a body, a blade, a feed shaft, and a locking member. The body defines an axis and is adapted to be received by a spindle of a power tool. The blade is removably supportable on the body and rotatable about the axis for cutting a workpiece. A feed shaft is removably supportable in the body and rotatable about the axis for engaging a workpiece, the feed shaft being mountable in the cutting tool to engage and at least partially restrain the blade. The feed shaft further includes an opening transverse to the axis. The locking member is engageable with the body and with the opening in the feed shaft. Advancement of the locking member into the opening tightens both the blade and the feed shaft to the body.

A colleted bushing includes a collet and a bushing. The collet has a collet proximal end and a collet bore having collet threads. In addition, the collet has a collet bore taper located adjacent the collet proximal end, and a plurality of collet fingers located adjacent the collet proximal end and configured to be inserted into a workpiece hole of a workpiece. The bushing has a bushing proximal end, a bushing bore, a bushing outer surface, and bushing threads formed along a section of the bushing outer surface. The bushing is configured to be inserted into the collet bore and the bushing threads are configured to engage the collet threads in a manner resulting in movement of the bushing proximal end into contact with the collet bore taper causing the collet fingers to be urged radially outwardly and removably locking the collet within the workpiece hole.

A guide for a hole saw for making a new larger hole in a work piece with an existing hole, the guide comprising a base sized to span the existing hole, the base comprising a central aperture, a plurality of discrete first contact surfaces for abutting an interior cylindrical wall of the existing hole, and a plurality of discrete second contact surfaces for abutting an exterior surface of the work piece surrounding the existing hole; the plurality of discrete second contact surfaces being substantially co-planar and being substantially perpendicular to the plurality of discrete first contact surfaces; a shaft having a first end sized to be received in an arbor of the hole saw and a second end to be slidably and rotatably received through the central aperture of the base; and the base biased to be located at or near the second end of the shaft.

A drill bit configured for use with a rotary power tool including a chuck. The drill bit includes a shank including a first end and a second end, and a paddle that extends from the second end of the shank. The paddle includes a first face including a concave portion, a second face opposite the first face and the second face including a convex portion opposite the concave portion, a cutting surface, a cutting edge located at an end of the cutting surface, a relief angle defined by the cutting surface, and an angled rake face adjacent the cutting surface that defines a rake angle that is between about 5 degrees and about 45 degrees.

A cutting tool including a body, a blade, a feed shaft, and a locking member. The body defines an axis and is adapted to be received by a spindle of a power tool. The blade is removably supportable on the body and rotatable about the axis for cutting a workpiece. A feed shaft is removably supportable in the body and rotatable about the axis for engaging a workpiece, the feed shaft being mountable in the cutting tool to engage and at least partially restrain the blade. The feed shaft further includes an opening transverse to the axis. The locking member is engageable with the body and with the opening in the feed shaft. Advancement of the locking member into the opening tightens both the blade and the feed shaft to the body.

A method to repair a damaged area of a workpiece with a repair kit includes rotating an arbor to drive a cutting member about a central axis of the arbor, cutting a hole in the workpiece with the cutting member, engaging the workpiece with the cutting member as the hole is cut to secure the cutting member within the hole, disconnecting the arbor from the cutting member, and leaving the cutting member in the workpiece to plug the hole.

A retractable pilot bit comprises a stem defining a rotational axis and configured to rotate in a first rotational direction about the rotational axis, a collar coupled to the stem and configured to rotate in the first rotational direction, and a bit configured to rotate in a first rotational direction in a penetrating configuration and configured to rotate in a second rotational direction opposite the first rotational direction in a rotatable configuration.

A hole-saw comprises a cylindrical body, a plate, a mandrel, and a clamping member. A cutting edge is formed at an open end of the body and is disposed about the body's rotational axis. The plate is disposed at an opposite end of the body, is rotationally coupled to the body, and is oriented perpendicular to the body's rotational axis. In one embodiment the plate has lateral slots formed through the plate and lateral grooves formed in the plate's distal surface in an orientation transverse to the slots. The mandrel's proximal section forms an arbor shaft, and its distal section includes lateral bosses sized to insert through the plate's slots and rest in the plate's grooves. The clamping member has a body that is movable along the mandrel's longitudinal axis to engage the plate's proximal surface and clamp the plate between the clamping member and the bosses resting in the plate's grooves. Other embodiments include a cylindrical body with a cutting edge at both ends. Either cutting edge can have an inner or an outer tooth to easily remove the plug. The pilot drill bit can have a burr to prevent jamming.

A method employing an apparatus in conjunction with a hammer-drill to penetrate composite metal and non-metal structure or structures including, for example, thick metal or rebar encountered during concrete, rock or masonry boring operations without requiring a change in drill equipment.