This 19mm (3/4 inch) grinding head with 9° and 18° miter, provides the ability to grind glasspieces at an angle. The miter is 9° or 18°, which is ideal to grind glass parts that join on the edges. For example, in lamps and other three-dimensional objects. Get cleaner, narrower solder lines on your lamps. For lamps with ten or more panels the 9 ° angle is chosen, use the 18° angle for less than ten panels.