The class of coners with which we now have to do, is represented by the cutting tool attached to the breast-brace or hand-brace, shown in Fig. 276 ; such a coner consists of a semi-conical cutter, which is rotated by the brace, and cuts away the metal at the mouth of a recess until it is formed to the depth and width required. Coners of this class are used to shape the centre recesses in the ends of rods and axles when a coning punch is not adapted to form the recess to the necessary dimensions; through the taper form of such a cutter, it will shape recesses of various sizes, according to the dimensions of the work to be coned, and a coning punch may be afterwards hammered into the recess to smooth the sides, if necessary. Coning with such a cutter is easily effected in iron or gun-metal; but to form a conical recess into steel, it is advisable to first cut away the metal with a gouge (Fig. 275), and next hammer a coning punch into the recess to smoothly form it to the required shape.