A tool insert includes first, second, and third teeth arranged on a surface of the tool insert. The first tooth is arranged at a proximal end of the tool insert surface and has an angled leading end and a first tooth height. The second tooth is spaced from the first tooth by a first distance along the surface of the tool insert and has a second tooth height greater than the first tooth height. The third tooth is spaced from the second tooth by a second distance along the surface of the tool insert and has an extending angled portion. The first tooth forms a first groove in a bore surface. The second tooth increases the depth of the first groove. The third tooth provides at least one micro-scratch to one of the first groove and the bore surface.

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 cutting element for a tool to create a helically extending, trapezoidally undercut groove in a cylindrical surface of a bore. The cutting tool, preferably configured as a cutting insert, has groove-cutting teeth to create a symmetrically cross-sectioned groove which are arranged in series in a division harmonized with the pitch of the groove to be created. These groove-cutting teeth comprise at least one pre-machining tooth to create and machine a base groove and several trapezoidal teeth following the at least one pre-machining tooth, which have a tooth head profile which expands trapezoidally in cross-section in the vertical direction of the tooth with two flanks delimiting a flank angle for further machining the base groove to a trapezoidally undercut final cross-section. The flank angle delimited by the two flanks increases from at least one trapezoidal tooth to a following trapezoidal tooth to a defined final dimension.

A round hole machining method and a round-hole machining device in which machining can be accurately performed regardless of a residual stress caused by casting. An out-of-round hole machining device, which carries out inner diameter machining for a bore in a cast cylinder block includes the following: a stress deformation amount correspondence table that stores, for each portion of the cylinder block, a stress deformation amount based on stress that resides in the cylinder block during casting; a machining shape prediction section that predicts the machining shape on the basis of the stress deformation amount read from the stress deformation amount correspondence table; and a motor control unit that reverses the predicted machining shape with respect to a target shape and carries out reverse machining on a workpiece.

In a method for a finishing work of a spray-coated surface, an inner surface of a cylindrical hollow member is roughened by forming a helical groove thereon. A thermal spray coating is formed on the inner surface that is roughened, and a finishing work is carried out by cutting the thermal spray coating along a helix of the groove by use of a cutting tool. According to the method for a finishing work, a finishing work of a thermal spray coating with non-uniform hardness can be carried out efficiently.

For producing a cylindrical surface that has a surface structure of predetermined geometry suitable for application of material by thermal spraying, a geometrically predetermined groove structure of minimal depth and width is introduced into the surface by a tool embodied as a follow-on tool in that a groove cross-section is processed successively to a final size. In order for the surface to be producible in mass production with constant quality, the groove structure is worked in such that first a base groove is introduced with a groove bottom width that is smaller than the groove bottom width of the finished groove. Subsequently, at least one flank of the base groove is processed for producing an undercut groove profile by a non-cutting action or cutting action wherein the introduced groove structure is deformed in such a way that the groove openings are constricted by upsetting deformations of material.

A method for mechanically roughening a cylindrical surface of a workpiece, e.g. the piston-bearing surface of a cylinder sleeve in a cylinder crankcase, by producing a defined microstructure of mutually crossing grooves, and by a groove forming tool, operating with or without material removal. A method in which in a first operation, a groove-forming tool is moved axially along the workpiece surface in such a way that at least one axial groove is machined into the workpiece surface; and in a second operation, following the first operation, the groove forming tool is rotated about the cylinder axis by a predefined rotational angle in the axial position reached in the first operation, whereby at least one circumferential groove crossing the axial groove is machined into the workpiece surface; and in a third operation following the second operation, the groove-forming tool is drawn back axially along the workpiece surface.