| 摘要 |
A frusto-conical multi-stage reamer constructed from a sequence of reamer stages is disclosed. Each reamer stage includes a central stem having a coupling at the leading end and a coupling at the trailing end. A plurality of circumferential arms extend from the central stem of each reamer stage and are inclined in a common direction with respect to the axis of the stems. The free ends of the arms are directed outwardly and forwardly with respect to the stem, and individual reamer teeth are attached to the free end of each arm. The radial extent of the arms of each stage of the sequence is a preselected increment greater than the radial extent of the arms of each preceding stage. In operation, the reamer stages are connected in sequence by the aforesaid couplings and simultaneously rotated and pulled through a pilot hole to produce an enlarged aperture.
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