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 method of machining a workpiece is provided that is capable of forming a fresh air inlet in an arbitrary position in an outer shell of a container. According to the present invention, a method of machining a workpiece is provided that includes: machining to form a round hole in a workpiece using a boring drill having a tubular end portion, the end portion provided with a flat surface and a notch, and having a blade on a side of the notch, by pressing the flat surface against the workpiece while rotating the drill to contact the blade with the workpiece.

A cutting tool for cutting a hole into a fluid transportation pipe and for retaining a cutting chip is provided. The tool (1) comprises a main body (2) having an end which is prolonged by a tapered part (3), the tool (1) further comprising an accommodation space (11), the tool being configured to receive a cutting chip in the accommodation space (11) via an opening (10) which extends at least from a geometrical apex (5) of the tapered part (3) to the periphery of the main body (61), and the tool (1) further has a cutting edge (4) extending at least from the geometrical apex (5) of the tapered part (3) to the periphery of the main body (2) of the cutting tool (1). The main body (2) is made of a material that differs from a material of which the cutting edge (4) is made.