| 摘要 |
A bi-center drilling tool comprises a main reamer region located eccentrically to an axis of rotation of the tool, and a leading cutting structure located ahead of the main reamer region, in the drilling direction, the leading cutting structure being located so as to apply a side loading to the drilling tool, the direction in which the side loading acts being such as to counter a side loading applied, in use, due to the main reamer region being eccentric to the axis of rotation.
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