| 摘要 |
<p>A hollow reamer for trial holes, esp. to be attached to a hollow trepanning tool, has a cylindrical body, screwed internally at one end for attachment to the cutter and screwed externally at the other for connecting to the train of boring bars. On the external surface of the reamer and extending to its head end, at least three cylindrically surfaced strips are formed by cutter diamonds set flush in a metal alloy. The strips taper and their circumference is largest at the rear end of the reamer, so that the cutting line similarly increases uniformly towards the back end. The reamer is used to maintain the diameter of a trial hole so that a worn trepanning tool can be replaced by a new unused one.</p> |
