Finned impact operated boring tool

Abstract From the Canadian patent

An impact operated boring tool comprises an elongated body having a forwardly tapered nose merging to a generally cylindrical housing, a generally circular array of fins projecting radially outwardly from said housing rearwardly proximate the juncture of the nose therewith and extending over a course of up to half the length of the tool along the surface of said housing. Each of the fins has a generally rectilinear cross-section throughout the major extent of the length thereof. The fins define a series of grooves therebetween having bottoms which are disposed at least as Ear from a longitudinal axis of the housing as the outer surface thereof.