Professional Instruments Company BLOCK-HEAD®, ISO, liquistatic, and custom spindles are used in many applications as the main spindle axis supporting a grinding wheel. A precision air bearing or liquistatic spindle has the advantage of extremely low synchronous and asynchronous errors. The low error motion, typically under one-millionth of an inch, translates into greatly improved geometry of the workpiece. In most applications of air bearing technology to machining processes a work-holding spindle provides improvement to the part geometry, and the grinding-wheel spindle provides improvements to surface finish. An important subtlety is that the low radial asynchronous errors of Professional Instruments Company’s spindle reduces the sub-surface damage in all materials, especially in the case of brittle materials.

Our five manufacturing facilities have almost 300 air bearing spindles in operation as workheads and grinding spindles. The four shown here represent I.D., O.D., rotary, and jig grinding applications. Our market position as both a producer and user of our own precision bearing technology makes us uniquely qualified to solve grinding spindle problems. Our goal in manufacturing BLOCK-HEAD® spindle components is to drive the geometric form errors into the surface finish. The addition of an air bearing to the grinding wheel spindle provides for improved surface finish and surface integrity as well.