Fig. 2001.
For tapers that are beyond the capacity of this device, and also for holding cutters to have their face teeth ground, the device shown in [Fig. 2000] is employed. Upon the slide f is fixed knee k (the corresponding parts to which are seen in the general view, [Fig. 1992]), whose disk face at r is graduated as shown. Piece s is pivoted by a pin passing through the hub of k and having a nut t to secure it in its adjusted position. s is bored to receive the cutter arbor h, and is split through so that by means of the screw at v the arbor may be gripped and locked in s. The stud w for holding the gauge g passes into a bore in the bracket x, and is secured therein by the screw at y, the lugs through which y passes being split through into the bore for w. As shown in the figure, the arbor h is set for grinding the side teeth of the cutter, but it is obvious that s being pivoted to k may be swung out of the vertical and to any required angle, so as to bring the face of the tooth that is to be ground horizontally beneath the emery wheel, as shown in [Fig. 2001], which represents an angular cutter in position. We have now to consider the adjustment of the cutter to the emery wheel, necessary in order that the cutting edges may be given the necessary clearance.
Fig. 2002.
First, then, suppose in [Fig. 2002] that the line a a represents the line of centres of the emery-wheel spindle and the cutter arbor, and if the front face b of the tooth be set coincident with this line, as in the figure, then the top of the tooth partaking of the curvature of the wheel that grinds it would have its heel c the highest; hence the edge at b could not cut.
Fig. 2003.
If, however, the line a a in [Fig. 2003], still representing the line of centres, we so set the gauge (g, [Fig. 1994]) that the heel c of the tooth comes up to line a a, then the curvature of the emery wheel would give clearance to the heel c, and therefore a cutting edge to face b of the tooth.