A step drill bit includes a shank and a body having a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end, a terminal step at the proximal end, and a plurality of intermediate steps having incrementally increasing diameters disposed between the first and terminal steps. The step drill bit also includes a plurality of cutting edges each disposed along one of the plurality of steps. Each edge defines a helix angle and a radial rake angle. The radial rake angle and the helix angle of the cutting edge at the terminal step is greater than the radial rake angle and the helix angle of the cutting edge at the first step.

A deburring tool includes a shank attached at a first end to a chuck and a working portion at a second end of the shank. The working portion includes a first end portion closest to and joining the second end of the shank at a first end of the first end portion, a second end portion furthest from the shank, and an intermediate portion disposed between the first end portion and the second end portion, a first end of the intermediate portion joining a second end of the first end portion and a second end of the intermediate portion joining a first end of the second end portion. The intermediate portion tapers continuously from a largest diameter at the first end of the intermediate portion to a smallest diameter at the second end of the intermediate portion, and deburring cutter members provided on the second end portion adjacent the second end of the intermediate portion.

A drilling tool, in particular a reamer, for drilling out a workpiece core bore to a nominal diameter by means of a main blade formed on a drill body is disclosed. The main blade has a radially external cutting edge which extends along a drill-body longitudinal axis as far as a blade corner arranged at the drill tip, wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core bore with a rotary movement and a feed movement. The drilling tool has at least one groove blade which is arranged so as to precede the blade corner of the main blade in the direction of rotation of the tool. During the drilling-out operation, the groove blade produces a groove in the inner wall of the core bore drilling, the blade corner of the main blade being guided in the groove with an at least reduced cutting load.

A step drill bit including a shank operatively couplable to a tool, a body portion coupled to the shank, the body portion including a tool bit tip and a plurality of progressively sized, axially stacked steps, the body portion defining a hollow cavity, and an inner structure having a plurality of support members extending within the hollow cavity.

A drill bit includes a shank extending along a bit axis and a body with a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end and a terminal step at the proximal end. The drill bit also includes a flute in the body. The flute defines an elongated groove that extends from the distal end to the proximal end. The drill bit further includes a plurality of cutting edges formed in the body. Each cutting edge is disposed along one of the plurality of steps and defines a helix angle and a rake angle. The helix angle of the cutting edge at the terminal step is greater than the helix angle of the cutting edge at the first step. A ratio of the helix angle to the rake angle of the cutting edge at the first step is in a range from 0.5 to 2.4, and a ratio of the helix angle to the rake angle of the cutting edge at the terminal step is in a range of 0.9 to 1.7.

A step drill bit includes a shank and a body having a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end, a terminal step at the proximal end, and a plurality of intermediate steps having incrementally increasing diameters disposed between the first and terminal steps. The step drill bit also includes a plurality of cutting edges each disposed along one of the plurality of steps. Each edge defines a helix angle and a radial rake angle. The radial rake angle and the helix angle of the cutting edge at the terminal step is greater than the radial rake angle and the helix angle of the cutting edge at the first step.

A drill bit includes a shank extending along a bit axis and a body with a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end and a terminal step at the proximal end. The drill bit also includes a flute in the body. The flute defines an elongated groove that extends from the distal end to the proximal end. The drill bit further includes a plurality of cutting edges formed in the body. Each cutting edge is disposed along one of the plurality of steps and defines a helix angle and a rake angle. The helix angle of the cutting edge at the terminal step is greater than the helix angle of the cutting edge at the first step. A ratio of the helix angle to the rake angle of the cutting edge at the first step is in a range from 0.5 to 2.4, and a ratio of the helix angle to the rake angle of the cutting edge at the terminal step is in a range of 0.9 to 1.7.

The present disclosure provides a multi-groove pagoda drill bit. A circumferential wall of a tapered body is provided with a diameter-expanding step increasing in diameter from front to back. A plurality of primary helical grooves extending from a rear end to a front end and a plurality of secondary helical grooves extending from the rear end to close to the front end are opened on the circumferential wall of the tapered body. An axial cutting blade same as a cutting trajectory is disposed on groove mouths of the primary helical grooves and the secondary helical grooves. On a radial section of the tapered body, a front recess segment located at a side of a line connecting an edge tip and an axis and close to the edge tip is disposed in the groove mouths of the primary helical grooves and the secondary helical grooves.

A deburring tool includes a shank attached at a first end to a chuck and a working portion at a second end of the shank. The working portion includes a first end portion closest to and joining the second end of the shank at a first end of the first end portion, a second end portion furthest from the shank, and an intermediate portion disposed between the first end portion and the second end portion, a first end of the intermediate portion joining a second end of the first end portion and a second end of the intermediate portion joining a first end of the second end portion. The intermediate portion tapers continuously from a largest diameter at the first end of the intermediate portion to a smallest diameter at the second end of the intermediate portion, and deburring cutter members provided on the second end portion adjacent the second end of the intermediate portion.

A drilling tool, in particular a reamer, for drilling out a workpiece core bore to a nominal diameter by means of a main blade formed on a drill body is disclosed. The main blade has a radially external cutting edge which extends along a drill-body longitudinal axis as far as a blade corner arranged at the drill tip, wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core bore with a rotary movement and a feed movement. The drilling tool has at least one groove blade which is arranged so as to precede the blade corner of the main blade in the direction of rotation of the tool. During the drilling-out operation, the groove blade produces a groove in the inner wall of the core bore drilling, the blade corner of the main blade being guided in the groove with an at least reduced cutting load.