Milling head structure mounted in propelling machine e.g. drilling machine, has main cutting edge portion that is set back in proximal direction, relative to distal end of cylindrical jacket surface portion

摘要

The milling head structure (1) has a cylindrical jacket surface portion (4) that is aligned in coaxial with the centering rod (2). The distal end (3) of centering rod is arranged in the proximal direction. The teeth (6) are formed distal end (5) of cylindrical jacket surface portion. A main cutting edge portion (7.1,7.2) for lifting out of chips, is connected between centering shaft and cylindrical jacket surface portion. The main cutting edge portion is set back in the proximal direction, relative to the distal end of cylindrical jacket surface portion.