| 摘要 |
A hole opener for enlarging the diameter of bore holes, having a plurality of cantilevered spindles (6) for supporting rotatably attached cutter shells (9 ) having hardened surfaces for cutting and crushing to widen the bore hole. The cutte r shells are supported on an inner threaded journal (13) which permits a plurality of load bearing rollers or bearings (26) to facilitate rotational movement of the cutter. The hole opener is provided on a tubular body which is connected in a drill stri ng and which provides jetting nozzles (4) to remove the cutting debris and return i t to the earth's surface. The cantilevered support spindle (6), journal (13) and cutt er shell (9) assembly permit flexible interchange of cutter faces and sizes to be available for use with the same hole opener body and different directions of travel of the body.
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