| 摘要 |
A drilling tool set includes a plurality of drilling tools having different operative drill diameters to blast drill holes of different respective diameters. Each drilling tool of the set has a basic body defining a central axis of rotation, and two replaceable indexable bits including a center bit and a periphery bit which are mountable in respective center and periphery pockets formed in a front end of the basic body. The periphery bits of the respective drill tools of the set are identical, and the center bits of the respective drill tools of the set are identical. Each of the center and periphery pockets of each drill tool defines a radial center point. A first of the drill tools has a smaller operative drill diameter than a second of the drill tools. The first tool includes a first periphery pocket and a center pocket. The center point of the first periphery pocket is disposed closer to the axis than is the center point of the second periphery pocket. The center point of the first center pocket is disposed closer to the axis than is the center point of the second center pocket.
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