| 主权项 |
1. A drilling tool comprising:
a support shank including a fluted region having a number of flutes formed therein, a central recess formed in an end face of the fluted region, and a pair of receptacles formed adjacent the central recess; and an interchangeable cutting insert having a fastening pin, a pair of peripherally arranged lobes, an asymmetrical main lip divided into a guide lip and a clearance lip each being associated with a respective one of the peripherally arranged lobes, the guide lip having a supporting land and a guide land trailing the supporting land formed on the peripherally arranged lobe associated therewith, and the clearance lip having a trailing clearance portion formed on the peripherally arranged lobe associated therewith, wherein the fastening pin is disposed in the central recess and each lobe of the peripherally arranged lobes is disposed in a respective one of the receptacles, wherein a guide land and a supporting land are formed on the lateral surface of the support shank and each extend to a radial extent generally equal to the guide land and supporting land such that the guide land and the supporting land continuously extend the guide land and the supporting land, respectively, of the cutting insert, wherein the guide land and supporting land are structured to guide the drilling tool on the inner wall of the drill hole during a drilling operation, wherein the guide land and the supporting land define a secondary flank having a reduced radial extent relative to the supporting land and the guide land extending from the supporting land to the guide land, and wherein the guide land and one of the number of flutes define a second secondary flank therebetween, the second secondary flank extending along the receptacle of the support shank in which the lobe of the cutting insert associated with the guide lip is disposed therein. |
