A rotary cutting tool with an elongate body disposed about a longitudinal axis, the elongate body including a helical flute and a polycrystalline-diamond cutting tip. The cutting tip comprises an inner portion having an inner point angle and an outer portion having an outer point angle different from the inner point angle.

A rotary cutting tool comprises an elongate body disposed about a longitudinal axis, the elongate body including a helical flute and a polycrystalline-diamond cutting tip. The cutting tip comprises an inner portion having an inner point angle and an outer portion having an outer point angle different from the inner point angle.

A twist drill has a shaft and a flute portion, which extends between a drill tip and the shaft and has at least two flutes, which run helically around it at an angle of twist, are separated from one another by two webs and have a land extending between the flutes on the circumference of the flute portion. In order to provide a twist drill that has the features mentioned at the beginning, has better lubrication of the round bevels, less wear, improved guidance and improved concentricity, at least two round bevels that are spaced apart from one another are provided on each land and extend on the land at an angle of inclination in relation to the drill axis that is greater than the angle of twist but less than 90.

A cutting tool 10 includes: a shank part 14 that is substantially cylindrical in shape and provided at a base end portion 10b of the cutting tool 10; a cutting edge 18 located at a leading end portion 10t of the cutting tool 10; a chip discharge groove 30 formed from the cutting edge 18 toward the base end portion 10b of the cutting tool 10, for guiding and discharging chips generated during cutting; and a plurality of groove-like coolant flow paths 40 provided on a periphery of the cutting tool 10, for supplying coolant toward the leading end portion 10t. In a leading end view where the cutting tool 10 is viewed from the leading end portion 10t along the central axis 10A extending in a longitudinal direction of the cutting tool 10, a first coolant flow path 41 of the plurality of coolant flow paths 40 is located at an upper side relative to the cutting edge 18.

When viewed along a central axis, a start point phase of a first discharge flute falls within a range of not less than +10 and not more than +90 with respect to a central edge, an end point phase of the first discharge flute falls within a range of not less than 40 and not more than 0 with respect to the central edge, a start point phase of a second discharge flute falls within a range of not less than +10 and not more than +90 with respect to an outer peripheral edge, and an end point phase of the second discharge flute falls within a range of not less than 40 and not more than 0 with respect to the outer peripheral edge. The first discharge flute includes a first front flute portion, and a first rear flute portion contiguous to the first front flute portion.

An annular hole cutter includes a cutter body having cutting teeth and a plurality of flutes extending from the cutting teeth around a side wall between a first and second end, with the flutes separated from each other by a land. The hole cutter includes side walls defining primary and secondary flutes with each one of the primary flutes defining first and second helix angles, and with each one of the secondary flutes defining a third helix angle and a fourth helix angle, with the second helix angle being greater than the first helix angle.