| 摘要 |
FIELD: process engineering. ^ SUBSTANCE: proposed drill comprises body, inner cutting plate arranged nearby rotational axis and having axis of symmetry and axially symmetric shape. It has four cutting edges, four rounded angles, and outer cutting plate identical to said inner plate. Note here that outer cutting plate is arranged farther from rotational axis then inner plate. Trajectories of inner and outer plate rotation are at least partially superimposed to form overlap whereat cutting edges of both plates are inclined to rotational axis in direction toward machined part while trajectory of inner plate cutting edge rotation extends farther toward machined part along body rotational axis with respect to that of outer plate. ^ EFFECT: higher efficiency, ease of use. ^ 9 cl, 14 dwg |
