Core cutter and cutting method using the same

A core cutter comprising:

• a cylindrical body;
• and
• a tipped bit that is disposed in a manner to protrude from a distal end of the body, wherein
• the core cutter is configured to cut a workpiece with the bit when the body is rotated about a rotational axis that is an axis of the body,
• at the distal end of the body, a notch is formed adjacently to the bit at a position forward of the bit in a rotation direction of the body,
• a width of the notch in a circumferential direction of the body at the distal end of the body is less than or equal to 1.0 mm,
• the bit includes:
• a protruding portion that protrudes from the distal end of the body;
• and
• a fixed portion fixed to the body, the fixed portion being located proximal to the distal end of the body,
• the notch includes:
• a distal end portion;
• and
• a main portion continuous with a proximal end of the distal end portion,
• a width of the distal end portion in the circumferential direction of the body is less than or equal to 1.0 mm,
• a width of the main portion in the circumferential direction of the body is greater than 1.0 mm, and
• a proximal end of the main portion is positioned closer to a proximal end of the body than a proximal end of the fixed portion of the bit.

A cutting method using a core cutter,

• the core cutter including:
• a cylindrical body;
• and
• a tipped bit that is disposed in a manner to protrude from a distal end of the body, wherein
• the core cutter is configured to cut a workpiece with the bit when the body is rotated about a rotational axis that is an axis of the body,
• at the distal end of the body, a notch is formed adjacently to the bit at a position forward of the bit in a rotation direction of the body, and
• a width of the notch in a circumferential direction of the body at the distal end of the body is less than or equal to 1.0 mm,
• the cutting method comprising:
• a first step of providing the core cutter, an electric drill to which the core cutter is to be mounted as a distal end tool, and the workpiece having irregularities on a surface thereof;
• a second step of mounting the core cutter to the electric drill after the first step;
• and
• a third step of pressing a distal end side of the core cutter against a rising portion of the irregularities along a rising direction of the rising portion while rotating the core cutter by the electric drill about a rotational axis that is an axis of the core cutter to cut a part of the irregularities after the first and second steps.

A cutting method comprising:

• a first step of providing
• a core cutter including a cylindrical body and a tipped bit that is disposed in a manner to protrude from a distal end of the body, the core cutter being configured to cut a workpiece with the bit when the body is rotated about a rotational axis that is an axis of the body,
• an electric drill to which the core cutter is to be mounted as a distal end tool,
• the workpiece having at least two projections on a surface thereof, and
• a jig including a base portion, a cylindrical portion, and a through-hole, the base portion being placeable on the workpiece such that a bottom surface of the base portion is in contact with upper ends of the respective at least two projections, the cylindrical portion being provided upright at a center of an upper end of the base portion, the through-hole being drilled in the jig from the bottom surface of the base portion to an upper end of the cylindrical portion, the through-hole corresponding to an external diameter of the body of the core cutter;
• a second step of mounting the core cutter to the electric drill after the first step;
• and
• a third step of, after the first and second steps,
• placing the jig on the workpiece such that the through-hole of the jig on a bottom surface side of the base portion is positioned between the at least two projections of the workpiece, and such that the bottom surface of the base portion is in contact with the upper ends of the respective at least two projections,
• fixing the bottom surface of the base portion of the jig, the bottom surface being in contact with the upper ends of the respective at least two projections of the workpiece, to the upper ends of the respective at least two projections of the workpiece by stepping on a top surface of the base portion of the jig by feet of an operator, and then
• inserting the core cutter into the through-hole of the jig placed on the workpiece from an upper end side of the jig while rotating the core cutter by the electric drill about a rotational axis that is an axis of the core cutter, and pressing a distal end side of the core cutter against a rising portion of the at least two projections along a rising direction of the rising portion to cut a part of the at least two projections.