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 includes a cylindrical body having a sidewall with a first end and a second end opposite the first end. The cylindrical body includes a gullet formed in the sidewall between a leading surface, a trailing surface, and a bottom surface of the sidewall. The gullet defines a central longitudinal axis extending between the first and second ends of the sidewall that is obliquely oriented relative to a rotational axis of the hole saw such that the gullet is angled from the first end to the bottom surface in a direction toward a cutting direction of the hole saw. The gullet has a dimension measured parallel to the rotational axis between the first end of the sidewall and the bottom surface of the gullet that is greater than 1.5 inches. The hole saw includes a cutting tooth coupled to the first end of the sidewall adjacent the gullet.

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 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 includes a cylindrical body having a sidewall with a first end and a second end opposite the first end. The cylindrical body includes a gullet formed in the sidewall between a leading surface, a trailing surface, and a bottom surface of the sidewall. The gullet defines a central longitudinal axis extending between the first and second ends of the sidewall that is obliquely oriented relative to a rotational axis of the hole saw such that the gullet is angled from the first end to the bottom surface in a direction toward a cutting direction of the hole saw. The gullet has a dimension measured parallel to the rotational axis between the first end of the sidewall and the bottom surface of the gullet that is greater than 1.5 inches. The hole saw includes a cutting tooth coupled to the first end of the sidewall adjacent the gullet.

A coring unit comprises a clamping arrangement for releasably attaching the coring unit to a structure into which a core is to be cut. A bit is provided comprising an elongated tubular body having a cutting surface at a first circular end of the elongated tubular body for cutting the core. The unit includes a drive system adapted to rotate and linearly translate the bit so that the drive system rotates the bit and moves the bit with respect to the clamping arrangement to advance and retreat the bit through the structure to cut the core from the structure. A method of using the coring unit is also described. The unit and method permit an accurate, reliable, safe, and reproducible cutting of a hole in a structure. The unit and method find particular application in cutting holes in studs of wood frame structures to accommodate services such as wires and piping.

The present disclosure describes and teaches a drill safety system including a magnetic unit, a vacuum unit, and an improved hole saw drill set. The various parts of the drill safety system may be used individually or in combination with one another. The user may use the magnetic unit to surround the drilling site so that metal drill shavings on the drill surface may be collected by the magnetic unit. In addition, the magnetic unit includes a flippable top mechanism, allowing convenient disposal of the debris. The vacuum unit is fitted to the inner surface of the drilling site, collecting debris that fall through. The improved hole saw prevents over-penetrating by the drill, reducing the likelihood of damaging equipments underneath the drill site. This makes the drill particularly suitable for drilling holes during electrical work.

A quick-release arbor is adapted for a cylindrical hole saw that has a bottom wall having a threaded central aperture and opposing indexing holes. The arbor has a central hexagonal passage with opposing key slots passing therethrough and a threaded hole saw fitting axially aligned with the hexagonal passage. The arbor has a hexagonal pilot shaft securely holding a pilot drill bit and intermediate opposing keys forming a position lock. The pilot shaft is adapted to freely pass through the passage. Within the arbor is a button chamber that is transverse to the hexagonal passage with a rear wall. A biased button is located within the button chamber having upper and lower cuts outs to permit the pilot shaft to freely pass through the cut outs of the button when the button is depressed and having rear pocket to capture one of the pilot shaft opposing keys when the button is released.

A system is disclosed for releasable coupling of a hole saw to a drill arbor. The system includes an elongate drill arbor configured at a first end to be clamped in a drill chuck of a drill, and a hole saw adapter provided with a longitudinal bore in which the drill arbor can be received so that an inner surface of the longitudinal bore of the hole saw adapter is mounted slidably on an outer surface of the drill arbor in the longitudinal direction of the drill arbor. The drill arbor includes an actuator member and at least one retaining element co-acting therewith. The inner surface of the longitudinal bore of the hole saw adapter is provided with a recess into which the retaining element of the drill arbor can protrude.

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 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.