Raise boring head and stem assembly method

摘要

An improved method for assembling a stem within a mating, close fitting hole of a raise boring head by attaching an overhead beam to the body of the raise boring bit, supporting the stem with its longitudinal axis aligned with that of the beam and that of the mating hole, and moving the stem along its axis to assemble the stem in the mating hole. A coating of wear resistant material on selected regions of the stem employs a softer material than that of the stem or the mating hole to minimize damage to the hole during assembly.