A combination system of fixed arbor hole saws and quick-change mandrel that enables a user to drill multiple of same sized or different sized holes in desired substrate in a quick and hassle-free manner. A drill bit held and retained in the quick-change mandrel serves as a common pilot for all different fixed arbor hole saws. The combo system requires a single common quick lock mandrel that positively locks a hole saw on insertion. The securely locked hole saw can be released with easy pull on a collar in the mandrel. Also, the cut-out slug of any substrate is very easy to remove once the hole saw is released from the mandrel.

A positioning aid is disclosed for a core drilling machine, having a core drill for creating a hollow-cylindrical drill hole. The positioning aid includes a light source for creating a centring pattern on a workpiece. The positioning aid is fastened in a releasable and centered manner to the core drilling machine. The positioning aid may include a laser pointer, which is releasably fastened to a centring pin.

A safety drilling tool having a tapered drill bit that drills through materials, such as metal, without producing any torque or heat is provided. The safety drilling tool may provide safety for the operator of the tool while drilling or cutting into electrical/electronic enclosures, such as switchgear. The bit may include a smooth graduated cam on the cutting portion eliminate the usage of steps as is the conventional practice in the art. The drill bits may be different sizes to reduce the bulkiness for sake of convenience. The bits may have a one or more internal helical flutes for pushing the debris through the hole being drilled. The hole saw portion of the bit draws the material into the center of the bit until the initial hole is made allowing the debris from the tapered bit to flow through hole being drilled.

A hole saw assembly having a drive shaft, drive disk and hole saw blade. The drive disk has a plurality of radially extending projections that engage with engagement slots in the side of the hole saw blade.

A general purpose hole saw guide and a method of forming holes through surfaces, without the need of a centering bit, are provided. The hole saw guide includes a circular disk with concentric grooves on its surface. The disk is transparent and portable for placement on a surface through which a hole is to be drilled to facilitate the centering and stabilizing control of a hole saw on the surface. The method includes the steps of providing a transparent disk having concentric grooves; positioning the disk on a surface; mounting the disk to the surface; inserting a hole saw that is fitted to a drill into the grooves of the disk; drilling a hole through the disk and surface beneath it; and removing the disk from the surface after the hole has been drilled.

The hole saw with threadably removable portion is an improved hole saw that includes a removable portion that is able to slide back and forth with respect to an outer drill bit. The outer drill bit includes internal threadings along an inner surface, which correspond with external threadings provided on an outer surface of the removable portion. When the hole saw has bored a hole into an object, a core remains inside of the outer drill bit. The rotation of the drill rotates the removable portion with respect to the outer drill bit in order to push the core out of the outer drill bit. The outer drill bit includes a shoulder, which works in concert with the removable portion so as to lock the components together when in use as a hole saw.

A center locator is operated with a hole center for enlarging a round opening and includes a center seat having a through hole centrally defined therein, wherein the through hole is adapted to allow a centering drill of the hole cutter extending through the center seat. At least one adjusting device is longitudinally mounted to the center seat and formed with an engaging portion, wherein the at least one adjusting device is expandable relative to the center seat for adjusting a distance between the engaging portion of the at least one adjusting device and a center of the center seat.

A tool attachment, in particular hole saw, for a power tool having a driving axle that is drivable in oscillation. The tool attachment including a connecting device with which the tool attachment is attachable to the power tool such that the driving axle thereof and a tool axis essentially coincide. A work area has teeth, with the work area being at least partially circular in design and adjoining a hollow, cylindrical base. Openings are formed in the base, the openings constituting at least 60%, at least 80%, or at least 90% of the area of the base.

Wood core drilling bits for use in wood frame construction of structures in the residential and/or commercial market and sets of the same have a cylindrical barrel defining an axis of rotation and a first end that is open and a second end defined by a hub having a bore therethrough. The open end defines a plurality of cutting teeth and the cylindrical barrel defines a plurality of slots radially therethrough. The plurality of slots are positioned as points of a three-dimensional curve turning about the axis of rotation while moving parallel to the axis of rotation.

The present invention relates to a hole saw that is mounted on an electric drill to cut a hole formed on a flat plate such as a ceiling, and more particularly, to a hole saw with hole enlargement guide and support pieces detachable therefrom that is capable of cutting a hole with a larger size (diameter) than a hole already cut in a ceiling.