This process is used to clean and restore a glazed and loaded grinding wheel by cutting the surface back to its original sharpness. By diamond dressing the wheel, dull grains, swarf, and excess bonding material are removed, leaving sharp new cutting particles exposed.
Truing is the process in which the contact face of the grinding wheel is formed to run absolutely true with the work. This is essential for precision grinding because an out-of-true wheel will produce chatter marks. Both dressing and truing are done with the diamond dresser in a process simply called dressing.
The "C" clamp holder of the Themac dresser has been designed to clamp onto work in the lathe. Care should be taken to see that the diamond is set at the horizontal centerline of the grinding wheel. This is necessary to assure accurate truing of the face of the wheel. The grinding wheel should be passed very slowly across the diamond taking a very light cut, not more than two or three thousandths at a time. For a finer finish, a cut of .001 or less should be used with a very slow traverse.
Care should be taken to dress the face of the wheel on the side where it will contact the workpiece. A properly dressed wheel will have a wheel face that is absolutely parallel to the work being ground. Unless the wheel is at the point where it contacts the work, the operator is not certain that the wheel and work are parallel.
In dressing wheels on a long unsupported extension spindle, there is a tendency for the diamond to dig in. This does not mean that the spindle is malfunctioning, but it does prevent the operator from properly dressing the wheel. To overcome this condition, the wheel speed should be decreased.