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 cutting section (11) which is connectable to a drill shaft section via a releasable connecting device. The cutting section includes a first open tubular element (14) which is in the form of a first hollow cylinder having a first waved, trapezoidal or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is in the form of a second hollow cylinder having a circular ring-shaped cross-sectional area, and one or more drill segments (16) which are connected to the first open tubular element (14) and to the second closed tubular element (15).

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 method for producing a drill shaft for a wet drill bit includes forming N, where N≥1, strip materials into a tubular body where the tubular body is integrally joined at strip edges of the strip materials by N connection welds. At least one strip material of the strip materials is provided with at least one recess before the integral joining of the strip edges.

Provided are a guide pad having sufficient strength and a gun drill having the guide pad. A guide pad includes: a first surface; a second surface that is a flat surface located at a position opposed to the first surface; and a third surface that connects the first surface and the second surface to each other. When viewed along a rotational center axis, the first surface is a circular-arc-shaped surface, and when a point at which a virtual line passing through a circular-arc center of the first surface and perpendicular to the second surface and the second surface cross each other is assumed as a first point and a point at which a central axis of the through hole and the second surface cross each other is assumed as a second point, the first point is located at a position closer to the third surface than the second point.

There is provided a cutting insert used for both drilling and turning. The cutting insert includes an insert main body having a front surface and a rear surface, the outline shapes of which are parallelogram shapes, peripheral side surfaces disposed on four sides of the insert main body, cutting edges provided on respective intersecting ridge lines between the front surface and the peripheral side surface and between the rear surface and the peripheral side surface of the insert main body, and a hole provided in the insert main body to incline with respect to the front surface and the rear surface, the hole being usable for attachment.

An intelligent tungsten carbide cutter may include a shank, at least a cutting portion, and a sensor. The shank made of tungsten steel comprises a first end, a second end, and at least a first connecting portion, and the first connecting portion is located adjacent to the second end of the shank. The shank and the cutting portion are thermally connected through high frequency oscillation heating method, and the cutting portion is secured on the first connecting portion of the shank. An accommodating channel axially penetrates through a center portion of the first end of the shank and extends toward the second end, and the sensor is installed in the accommodating channel so as to be positioned close to the cutting portion, thereby achieving the direct and accurate sensing.

A method for producing a drill shaft for a wet drill bit includes forming N, where N≥1, strip materials into a tubular body where the tubular body is integrally joined at strip edges of the strip materials by N connection welds. At least one strip material of the strip materials is provided with at least one recess before the integral joining of the strip edges.

A cutting section (11) which is connectable to a drill shaft section via a releasable connecting device. The cutting section includes a first open tubular element (14) which is in the form of a first hollow cylinder having a first waved, trapezoidal or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is in the form of a second hollow cylinder having a circular ring-shaped cross-sectional area, and one or more drill segments (16) which are connected to the first open tubular element (14) and to the second closed tubular element (15).

A cutting section (11) which is connectable to a drill shaft section via a releasable connecting device. The cutting section includes a first closed tubular element (14) which is in the form of a first hollow cylinder having a first waved, trapezoidal or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is in the form of a second hollow cylinder having a circular ring-shaped cross-sectional area, and one or more drill segments (16) which are connected to the first closed tubular element (14).