Fig. 996.
Fig. 997.
[Figs. 996] and [997] represent a method of cutting a round top and bottom, or any other form of thread, by means of a single-pointed circular cutting tool, which is mounted on a holder. On the circumference of the cutter is cut a single thread, and a piece is cut out at e to form a cutting edge. To cut a right-hand thread on the work, a left-hand one must be cut on the cutter, so as to make its thread slant in the proper direction. The tool is sharpened by grinding the top face, and moved on the holding pin to set it to the proper height or in position to enable it to cut. A top view of the tool and holder is shown in [figure 997].
It is obvious that two gaps may be cut in the wheel or cutter so as to provide two cutting edges, one of which may be used for roughing, and the other for finishing cuts.
Fig. 998.