An indexable cutting insert has a central mounting portion and two cutting portions. The central mounting portion has opposing upper and lower surfaces. The lower surface has two abutment elements associated therewith, each abutment element having two diverging abutment surfaces forming two abutment angles. The two cutting portions extend away from the central mounting portion, have distal cutting edges, and are entirely located in diagonally opposite imaginary quadrants of four quadrants defined by two mutually perpendicular quadrant planes. Two abutment bisector planes bisecting the two abutment angles and one of the quadrant planes are parallel or coincident. In a top view, the two cutting portions extend away from the central mounting portion in opposite directions. Two cutting bisector lines parallel to the two directions and bisecting the two cutting edges are mutually offset. A cutting tool has an insert holder and the cutting insert removably retained therein.

To provide a cutting insert such that a tool body can sufficiently hold the cutting insert even if one of cutting parts is broken. The cutting insert includes two side surfaces opposed to each other, a fixing hole passing through the centers of the two side surfaces, and an outer circumferential surface that is disposed between the outer circumferential edges of the two side surfaces and are connected to the outer circumferential edges of the two side surfaces. The outer circumferential surface includes four cutting parts, a first outer circumferential surface part that is disposed between the first cutting part and the second cutting part, and a second outer circumferential surface part that is opposed to the first outer circumferential surface part and is disposed between the third cutting part and the fourth cutting part. In a side view of the side surfaces from the axial direction of the fixing hole, the first outer circumferential surface part and the second outer circumferential surface part each have the center recessed toward the fixing hole, and a virtual arc having the same diameter as the diameter of the circumcircle of the cutting insert is in contact with two points on each of the outer circumferential surface parts.

A cutting tool for turning includes a coupling portion, an intermediate portion and a cutting portion. The intermediate portion extends along a longitudinal center axis thereof between the coupling portion and the cutting portion. The cutting portion includes a first and a second nose portion. The first nose portion has a first cutting edge, a second cutting edge, and a convex nose cutting edge connecting the first and second cutting edges. The first and second cutting edges form a nose angle less than 90°. A longitudinal center axis of the coupling portion defines a tool rotational axis. The cutting portion includes a top surface, the top surface facing away from the coupling portion and the first and the second nose portions each form free ends of the cutting tool.

A tool body to which a replaceable cutting insert is fixed includes: a holder: an insert mounting seat that is provided on a first surface of the holder; a clamp member that constrains the cutting insert placed on the insert mounting seat; and an operating member that presses a pressure receiving surface of the clamp member. The clamp member has the pressure receiving surface, a spherical head portion that is formed into a spherical crown shape, and a hook portion that protrudes to a side opposite to a side of the spherical head portion when seen from a side of the first surface. The insert mounting seat supports the clamp member to be swingable with the spherical head portion as a fulcrum, and the hook portion contacts a diameter reducing portion that is formed on an inner peripheral surface of an mounting hole for the cutting insert in a state in which the pressure receiving surface is pressed.

A housing for an electric machine tool, in particular for a core drill, said housing in which a motor is accommodated, which has a motor shaft for driving a tool mount and to which cooling air is supplied through at least one air guide duct, which is delimited at one end by at least one air inlet and at the other end by at least one air outlet. A guide structure, providing air guidance for the cooling air and associated with a motor mount, in which the motor is at least partially accommodated, is disposed in the air guide duct downstream from the at least one air inlet.

A turning insert includes a head portion connected to a stem portion. A CBN cutting edge includes a surface generating cutting edge and two major cutting edge portions, such that each major cutting edge portion forms an angle of 5-20° in relation to a tangent line of the cutting edge at a forward point of the cutting edge.

A cutting insert and a cutting tool which can suppress lowering of blade-edge positional accuracy while holding by a holder having a small thickness is enabled are provided.

The cutting insert includes a first end surface, a second end surface, and a peripheral side surface connected to the first end surface and the second end surface and having a rake face, a flank, and a cutting edge formed in a connection region between the rake face and the flank, and a through hole penetrating the first end surface and the second end surface is formed. It is the cutting insert including a first contact surface substantially perpendicular to a center axis direction of the through hole and capable of contacting the holder, a second contact surface substantially in parallel with the center axis direction of the through hole, substantially perpendicular to a plane including the first contact surface and capable of contacting the holder, and a third contact surface inclined with respect to the center axis direction of the through hole and capable of contacting the holder, and a cutting tool including the cutting insert as above.

A turning insert includes a top surface, an opposite bottom surface, and a reference plane located parallel to and between the top and the bottom surfaces. A nose portion includes a convex nose cutting edge, and a first and a second cutting edge. The nose cutting edge connects the first and second cutting edges. The first and second cutting edges form a nose angle of 71-85° relative to each other. The nose portion has a third convex cutting edge adjacent to the first cutting edge and a fourth cutting edge adjacent to the third convex cutting edge. The fourth cutting edge forms an angle of 10-30° relative to a bisector. The distance from at least a portion of the fourth cutting edge to the reference plane increases at an increasing distance from the nose cutting edge. A second protrusion is arranged between the nose cutting edge and the first protrusion.

Provided is a cutting insert having two cutting parts that is capable of entering a workpiece more deeply and easily supports machining of a groove or hole having a small diameter in a workpiece. A cutting insert includes: a body having at least an inner surface to be fixed to a tool body of a cutting tool and an outer surface opposed to the inner surface; and two cutting parts protruding in opposite directions in a longitudinal direction of the body. The cutting part includes: a cutting upper surface; a cutting front surface; and a first cutting side surface and a second cutting side surface. A front cutting edge is located on an edge between the cutting upper surface and the cutting front surface. In a projection view of the body as seen from the longitudinal direction, the cutting upper surfaces of the two cutting parts are oriented in directions opposed to each other, and front cutting edges of the two cutting parts are disposed so as to be more away from each other as being closer to the first cutting side surface from the second cutting side surface.

A non-indexable, one-sided cutting insert includes opposite insert side surfaces which define an insert width therebetween, opposite insert front and rear surfaces which extend between the insert side surfaces and define an insert depth therebetween and opposite insert top and bottom surfaces which extend between the insert side surfaces and the insert front and rear surfaces. The insert top and bottom surfaces define an insert height therebetween. The insert further includes a main cutting edge formed at an intersection between the insert top and front surfaces. A maximum value of the insert width is smaller than minimum value of the insert height, and a minimum value of the insert depth. The insert includes a deep opening which opens out only to the insert bottom surface and defines an opening depth. A depth ratio defined between the opening depth and the insert height is greater than 0.3.