Fig. 1090.
Fig. 1091.
It would appear that this defect might be remedied by placing the emery-wheel parallel to the teeth as in [Fig. 1090]; but if this were done, the wear of the emery-wheel would cause the formation of a shoulder at s in the figure, which would round off the cutting edge of the tooth. This, however, might be overcome by giving the emery-wheel enough end motion to cause it to cross and recross the width of the top facet; or the reamer r may be presented to the wheel w at an angle to the plane of wheel rotation, as in [Fig. 1091], which would leave a straight instead of a curved facet, and, therefore, a stronger and more durable cutting edge.
Fig. 1092.
Another method of accomplishing the same object would be to mount the emery-wheel as in [Fig. 1092], using its side face, which might be recessed on the side, leaving an annular ring of sufficient diameter to pass clear across the tooth, and thus prevent a shoulder from forming on the side face of the wheel.