Download INSTRUCTIONS TO LEARN HOW TO USE A LATHE

In order to cut a round groove of a definite radius on a cylindrical surface, the tool bit
must be ground to fit the proper radius gage (Figure 7-57). Small V-grooves may be
machined by using a form tool ground to size or just slightly undersize. Large V-grooves
may be machined with the compound rest by finishing each side separately at the desired
angle. This method reduces tool bit and work contact area, thus reducing chatter,
gouging, and tearing. Since the cutting surface of the tool bit is generally broad, the
cutting speed must be slower than that used for general turning. A good guide is to use
half of the speed recommended for normal turning. The depth of the groove, or the
diameter of the undercut, may be checked by using outside calipers or by using two wires
and an outside micrometer (Figure 7-58).