Abstract
This paper discusses the bobbing of chip crush, which has become one of object of attention as diy cut. In the cutting tests using a fly-tool, the dimensions of the work piece were 500mm in length and SCM420. The hardness of that material is HB170. The tool was made of high-speed steel and TiAlN coated. As a result, the following conclusions were obtained: (1) TiAlN coated fly-tool was the wear track of the tooth flank in both cutting in and cutting out. (2) Up cut is better than down cut in the machined surface with TiAlN full coated fly-tool.
