METHOD IN EARTH DRILL BIT ARRANGEMENT ASSEMBLY AND A BIT ARRANGEMENT

摘要

The object of the invention is a method in an earth drill bit arrangement assembly and a bit arrangement. In the method at least the outer bit (3) of an earth drill is connected to a casing shoe (2) functioning as a coupling ring such that the outer bit (3) can be rotated in relation to the casing shoe (2) and can be moved a limited distance in the axial direction in relation to the casing shoe (2). For coupling the outer bit (3) to the casing shoe (2), the outer bit (3) is assembled, in connection with the coupling, from two essentially ring-like parts (3a, 3b) disposed consecutively in the axial direction of the drill.