A cutting tool is configured to cut and countersink a hole in a workpiece. The cutting tool includes a shank and a fluted body extending along an axis. The body includes a tip, a chamfer in an axially spaced relationship with the tip and a cross hole with a proximal end opening to the chamfer. The body has a cutting section extending between the tip and the chamfer, and a countersinking section extending along the chamfer. At the cutting section, the body includes at least one hole-cutting edge. At the countersinking section, the body includes a scalloped countersink-cutting edge along a junction of the chamfer and the proximal and of the cross hole.

A drill bit includes a pointed head and a bit shaft. A dust suction passage is formed in the bit shaft. A hole with an opening is formed in the pointed head or in a portion of the bit shaft, the portion being near a distal end of the bit shaft. The bit shaft includes a first portion, the first portion including a core and a rib. The core extends in an axial direction, and is thinner than the pointed head. The rib protrudes radially outward from a side surface of the core, and extends over an entire length of the first portion. The dust suction passage extends through the core in the axial direction.

A round hole machining method and a round-hole machining device in which machining can be accurately performed regardless of the wear of an edge tool. A non-round hole machining device includes: a machining load data acquisition section for obtaining machining load data corresponding to a machining load acting on the cutting edge of a cutting tool when boring a bore in a cylinder block; a machined shape prediction section for predicting a machined shape of the workpiece by utilizing the obtained machining load data and elastic deformation amounts at respective positions on the workpiece; and a motor control section for machining the workpiece so as to form an inverted shape, that is, a shape formed by inverting the predicted machined shape with respect to a target shape.

A drill with a drill flute (12) includes symmetrical fluted lands (20) helically extend around a core, wherein grooves (18) remain between the fluted lands, said grooves having a width (72) that exceeds the spine thickness or width (24) of the fluted lands (20), and wherein the grooves (18) comprise a convex core reinforcement (22) at the groove bottom thereof. The width (24) of the fluted lands (20) at the drill head side end (16) is smaller than at the shank side end (14) of the drill helix (12), and at least increases in certain areas. The core reinforcement (22) at the drill head side end (16) is more convex than at the shank side end (14), thus has larger radii (40, 42).

A robotic building system includes a first through third sets of extruded elements integrally joined at lengthwise edges and corners to rails. The second set of extruded elements has at least three adjoining sides surrounding a hollow opening, where each side is integrally joined to a rail. A third set of extruded elements has an asymmetrical inside angle shaped element formed by a first web and a second web oriented generally perpendicular to the first web, where each web is integrally affixed between a pair of opposing rails and each web shares a common rail. The rails may be tapped or drilled to accept a fastener, and each extruded element of the first set, second set and third set of extruded elements are adapted to be flush mounted to any of the other extruded elements or to the same shape extruded elements.

A drill bit includes a pointed head and a bit shaft. A dust suction passage is formed in the bit shaft. A hole with an opening is formed in the pointed head or in a portion of the bit shaft, the portion being near a distal end of the bit shaft. The bit shaft includes a first portion, the first portion including a core and a rib. The core extends in an axial direction, and is thinner than the pointed head. The rib protrudes radially outward from a side surface of the core, and extends over an entire length of the first portion. The dust suction passage extends through the core in the axial direction.

A cutting head rotatable about a first axis, comprising an intermediate portion and a tip portion. The intermediate portion has a plurality of leading edges defining a cutting diameter, and the tip portion has an axially forwardmost tip point and a plurality of front surfaces with outer and inner cutting edges. An outer rake surface adjacent to each outer cutting edge has a positive outer rake angle, and an inner rake surface adjacent to each inner cutting edge has a negative inner rake angle. Each outer rake surface is disposed on a head flute intersecting one of the leading edges, and each inner rake surface is disposed on a gash intersecting one of the head flutes. Each gash extends to a gash path end point located a first distance axially rearward of the tip point, and the first distance is greater than thirty percent of the cutting diameter.

A drill includes a blade tip part that is formed of diamond and a trunk part that is formed of diamond and is continuous with the blade tip part, the drill rotating about a drill axis, the blade tip part includes N cutting edges where N is an integer of no less than 4, and a proportion of S1 to S2 is no less than 30% and no more than 60%, where S1 is an area of the drill in a cross-section with the drill axis as a normal line, the cross-section including a boundary between the blade tip part and the trunk part, r is a maximum value of a distance from the drill axis to an outer edge of the drill in the cross-section and S2 is an area of a circle with r as a radius.

A drilling insert includes a body having a length measured between a first end and a second end. The body includes a cutting head positioned at the first end of the body. The cutting head has a first maximum outer diameter. The body also includes a shank positioned at the second end of the body and configured to be coupled to a tool. The shank has a second maximum outer diameter that is less than the first maximum outer diameter. The body further includes a shaft extending between the shank and the cutting head. The shaft has a third maximum outer diameter that is less than the first maximum outer diameter. The shaft extends a majority of the length of the body. The drilling insert includes a cutting insert coupled to the cutting head and spanning over at least 50% of the first maximum outer diameter of the cutting head.

A rotary tool may include a base. The base may be extended from a first end to a second end. The base may include a first part and a second part. The first part may include the first end. The second part may have a larger outer diameter than the first part. The first part may include a first flute. The second part may include a second flute. In a first cross section of the first part, the first flute may include a first bottom part. A center of a first imaginary circle overlapping with the first bottom part may be located outside a circumscribed circle of the first part. In a second cross section of the second part, the second flute may include a second bottom part. A center of the second imaginary circle overlapping with the second bottom part may be located inside a circumscribed circle of the second part.