Rotatable tool for chip removing machining as well as a loose top and a basic body therefor

A loose top for rotatable tools for chip removing machining, comprising:

• a head including front and rear ends between which a geometrical center axis (C2) extends;
• and
• a centering pin protruding axially rearward from the rear end of the head, the centering pin including first and second diametrically opposed, external surfaces, each having an axial extension and a peripheral extension, the first external surface forming a contact surface that extends peripherally between two axially extending boundary generatrices, which are situated along an imaginary circle (S2) having a center (MP2) coinciding with the center axis (C2), and between which an arc angle (β) is less than 180°, the second external surface forming a clearance surface that extends peripherally from the two axially extending boundary generatrices and includes two part surfaces and a back surface,
• wherein the rear end of the head has a radially extending plane surface that extends radially outward of the contact surface and the clearance surface relative to the geometrical center axis,
• wherein, in a plane perpendicular to the center axis (C2) at a first axial position of the centering pin, a first radial cross-section of the centering pin includes a first contact surface and a first clearance surface,
• wherein, in the first radial cross-section, a greatest radial distance (RD2) between the center axis (C2) and a point on the first clearance surface is greater than the radius (r2) of the imaginary circle (S2) containing the first contact surface, and
• wherein, in the first radial cross-section, the two part surfaces converge in a direction from the first contact surface toward the back surface of the first clearance surface.

A basic body for rotatable tools for chip removing machining, comprising:

• an envelope surface and front and rear ends, between which a geometrical center axis (C1) extends,
• wherein the front end includes jaw delimited by two drivers and an intermediate bottom in which an axially extending center hole mouths, a hole for a screw extending between the center hole and the envelope surface,
• wherein the center hole is delimited by a cylindrical support surface, which is concentric with the center axis (C1) and which is positioned on a portion of a circle (S1) having a radius (r1), and by an opposite clearance surface situated radially outside an imaginary projection of the circle (S1), and
• wherein the center hole has a cross-sectional shape in which the clearance surface includes two part surfaces.