Abstract: A machining tool is rotated around an axis and includes a machining blade portion having a first machining blade in the distal end direction with respect to a rake face and a second machining blade located in the radially outward direction with respect to the rake face, and a protrusion formed on the rake face and having a tip for cutting chips coming from the first machining blade. The protrusion includes an inner forming portion that is located in the radially inward direction from the reference line and an outer forming portion that is located in the radially outward direction from the reference line, and the width of the inner forming portion is wider than the width of the outer forming portion.

Abstract: A machining tool is a machining tool rotated about an axis and is provided with a machining blade portion having a rake face and a machining blade, wherein in a case where the rake face faces and is parallel to an virtual plane including the axis, the rake face is arranged at a position shifted from the virtual plane in the direction opposite to the rotational direction of the machining tool.

Abstract: When forming a first preliminary flute on a PCD layer of a columnar body, electrical discharge machining is performed by setting the electrode orientation so that the first twist angle is ?. Next, when forming a second preliminary flute on a substrate of the columnar body and a round bar, the grinding process is performed by setting the grinding orientation and direction for a diamond whetstone so that a second twist angle is larger than the first twist angle.

Abstract: A machining tool is a machining tool rotated about an axis and is provided with a machining blade portion having a rake face and a machining blade, wherein in a case where the rake face faces and is parallel to an virtual plane including the axis, the rake face is arranged at a position shifted from the virtual plane in the direction opposite to the rotational direction of the machining tool.

Abstract: A machining tool is rotated around an axis and includes a machining blade portion having a first machining blade in the distal end direction with respect to a rake face and a second machining blade located in the radially outward direction with respect to the rake face, and a protrusion formed on the rake face and having a tip for cutting chips coming from the first machining blade. The protrusion includes an inner forming portion that is located in the radially inward direction from the reference line and an outer forming portion that is located in the radially outward direction from the reference line, and the width of the inner forming portion is wider than the width of the outer forming portion.

Abstract: When forming a first preliminary flute on a PCD layer of a columnar body, electrical discharge machining is performed by setting the electrode orientation so that the first twist angle is ?. Next, when forming a second preliminary flute on a substrate of the columnar body and a round bar, the grinding process is performed by setting the grinding orientation and direction for a diamond whetstone so that a second twist angle is larger than the first twist angle.

Abstract: A blade section has two lands and two flutes in an alternating manner and also has a linear chisel edge. The lands are each provided with: a margin section that is continuous with a cutting blade; a clearance section that is continuous with the margin section and that has a smaller diameter than the margin section; and a pad that is continuous with the clearance section and that has the same width as the width of the margin section.

Abstract: A blade section has two lands and two flutes in an alternating manner and also has a linear chisel edge. The lands are each provided with: a margin section that is continuous with a cutting blade; a clearance section that is continuous with the margin section and that has a smaller diameter than the margin section; and a pad that is continuous with the clearance section and that has the same width as the width of the margin section.

Abstract: A drill includes a blade portion provided with spiral cutting blades along a cutting direction from a tip end to a rear end, and a shank portion formed consecutively on a rear side of the blade portion. The blade portion includes distal-side cutting blades provided from the distal end of the blade portion along the cutting direction and angled at a constant first torsion angle, intermediate grooves formed at a variable torsion angle that varies gradually from the first torsion angle to a second torsion angle, and rear-side grooves formed at the constant second torsion angle. The rear-side grooves are longer than the distal-side cutting blades in the cutting direction, and the second torsion angle is greater than the first torsion angle.

Abstract: A drill includes a blade portion provided with spiral cutting blades along a cutting direction from a tip end to a rear end, and a shank portion formed consecutively on a rear side of the blade portion. The blade portion includes distal-side cutting blades provided from the distal end of the blade portion along the cutting direction and angled at a constant first torsion angle, intermediate grooves formed at a variable torsion angle that varies gradually from the first torsion angle to a second torsion angle, and rear-side grooves formed at the constant second torsion angle. The rear-side grooves are longer than the distal-side cutting blades in the cutting direction, and the second torsion angle is greater than the first torsion angle.