Hohlbohrwerkzeug und dieses Werkzeug verwendende Maschinen

摘要

Provided is a core drill (211) and a core-drill processing machine (240) for forming a hole into hard material, whereby the mechanical processing with reduction in the cutting and/or contact resistance to the tools is realized, so that in the case of the core drill (211), not only are grinding powder of a workpiece (W) and loosed-off abrasive grains effectively removed to prevent those from being loaded between the drill (211) and the workpiece (W), but neither of cracking and chipping occur when the drill (211) passes through the workpiece (W). A core drill (211) comprises: a shank (214); a base metal section (216) having a cup-like shape constructed of a disk-like top wall (216a) and a cylindrical side wall (216b) provided on a fore-end of the shank (214); a grinding stone portion (217) mounted on an outer end part of the base metal section (216); and abrasive grain layers (230a,230b) formed on inner and outer side surfaces of the cylindrical side wall (216b) of the base metal section (216).