| 摘要 |
A cutting insert for wellbore milling operations is disclosed which, in certain embodiments, has two or more top milling surfaces on an insert body with the surfaces at different heights above a bottom of the insert body. In certain embodiments three top surfaces are used stair-stepped, with a central lower surface, or with a central higher surface. In one aspect all cutting surfaces have an array of chipbreaking indentations. Tools and methods are disclosed which use such inserts. |
