A method for forming dimples on a workpiece includes providing a rotary cutting tool. The rotary cutting tool includes a cutting edge that protrudes in a leading direction parallel to a longitudinal axis of the tool. The cutting edge extends from a position at the leading end of the rod-shaped main body that is radially offset from the longitudinal axis. The rotary cutting tool is set such that the longitudinal axis of the rotary cutting tool is inclined relative to a line perpendicular to the processing surface of the workpiece. The rotary cutting tool is moved along the processing surface while the rotary cutting tool is rotated about the axis. The processing surface is cut by the cutting edge to form the dimples, which are spaced apart from each other on the processing surface.

A method for forming dimples on a workpiece includes providing a rotary cutting tool. The rotary cutting tool includes a cutting edge that protrudes in a leading direction parallel to a longitudinal axis of the tool. The cutting edge extends from a position at the leading end of the rod-shaped main body that is radially offset from the longitudinal axis. The rotary cutting tool is set such that the longitudinal axis of the rotary cutting tool is inclined relative to a line perpendicular to the processing surface of the workpiece. The rotary cutting tool is moved along the processing surface while the rotary cutting tool is rotated about the axis. The processing surface is cut by the cutting edge to form the dimples, which are spaced apart from each other on the processing surface.

A coated tool of the present invention includes a base material; and a hard coating film on the base material. The hard coating film is a nitride or carbonitride which contains aluminum (Al) of 65 atomic % or more and 90 atomic % or less and titanium (Ti) of 10 atomic % or more and 35 atomic % or less with respect to a total amount of metal (including metalloid) elements, and have a face-centered cubic structure. In the X-ray intensity distribution of the ? axis of the positive pole figure with respect to the (111) plane of the face-centered cubic structure, the hard coating film have a maximum intensity Ia in the ? angle range of 80? to 90? and an intensity in the ? angle range of 0? to 70? is 30% or less of the Ia.

A coated tool has a hard coating layer including a layer of a complex nitride or complex carbonitride expressed by (Ti.sub.1-xAl.sub.x)(C.sub.yN.sub.1-y). A periodic concentration variation is present in crystal grains of a complex nitride or complex carbonitride having a NaCl type face-centered cubic structure in the layer. The periodic concentration variation direction includes a direction at 30 degrees or less with respect to a surface of a tool body. An area percentage of a periodic concentration variation of Ti and Al is 40% or more. The concentration variation period is 1 to 10 nm. A difference between an average of local maximums and an average of local minimums of a periodically varying amount x of Al is 0.01 to 0.1. Fine crystal grains having a hexagonal structure with an average grain size of 0.01 to 0.3 m are present at grain boundaries in 5% or less of the area.

The hard coating layer includes at least a complex nitride or complex carbonitride layer expressed by the composition formula (Ti.sub.1-xAl.sub.x)(C.sub.yN.sub.1-y). The average Al content ratio x.sub.avg the average C content ratio y.sub.avg satisfy 0.60x.sub.avg0.95 and 0y.sub.avg0.005, respectively, each of the x.sub.avg and y.sub.avg is in atomic ratio. The crystal grains constituting the complex nitride or complex carbonitride layer include a crystal grain having the NaCl face-centered cubic structure. A predetermined average crystal grain misorientation exists in the crystal grains having the NaCl face-centered cubic structure.

A coated tool of the present invention includes a base material; and a hard coating film on the base material. The hard coating film is a nitride or carbonitride which contains aluminum (Al) of 65 atomic % or more and 90 atomic % or less and titanium (Ti) of 10 atomic % or more and 35 atomic % or less with respect to a total amount of metal (including metalloid) elements, and have a face-centered cubic structure. In the X-ray intensity distribution of the axis of the positive pole figure with respect to the (111) plane of the face-centered cubic structure, the hard coating film have a maximum intensity Ia in the angle range of 80 to 90 and an intensity in the angle range of 0 to 70 is 30% or less of the Ia.