Hohlbohrwerkzeug

摘要

The present invention relates to a core drill wherein initial drilling workability is improved through reduced frictional resistance on the segment tips, when they are seated on the surface of an article to start cutting operation, and wherein cutting scraps or sludge produced by the segment tips are smoothly discharged through the helical grooves formed on the core body so as to reduce the friction between the core body and the cutting scraps or sludge, whereby both the cooling and cutting performance of the core drill are improved. The invention proposes a core drill with a cylindrical core body with a predetermined diameter and length and with plural cutting segments provided on the lower part of a core body at a finite interval, wherein the cutting thickness surface of the cutting segment consists of inclined sharp thickness portion for decreased frictional resistance with an article to be processed.