MUCH HAS BEEN WRITTEN ABOUT SPINDLE BEARINGS, AND HOW CHANGES IN DESIGN OR MATERIAL RESULT IN IMPROVEMENTS. THESE ADVANTAGES HAVE NORMALLY ONLY BEEN SPELLED-OUT IN TERMS OF BEARING ACCURACY, STIFFNESS, OR SPEED CAPABILITY, AND IT HAS BEEN LEFT TO THE USER TO INFER THAT THIS WILL IMPROVE THE ACTUAL BEHAVIOR OF THE MACHINE TOOL. THE PURPOSE OF ANY GRINDING MACHINE IS TO REMOVE STOCK AND PRODUCE QUALITY PARTS, NOT TO SERVE AS A BEARING TEST STAND. THUS THIS PAPER, AFTER DISCUSSING MODERN SPINDLE BEARINGS AND THEIR CHARACTERISTICS, GOES ON TO OUTLINE THE POTENTIAL IMPROVEMENTS IN PRODUCTIVITY AND QUALITY PRODUCED BY CHANGING EITHER BEARING SPEED CAPABILITY OR STIFFNESS. IT CONCENTRATES LARGELY ON ANGULAR CONTACT BALL BEARING SPINDLES, AND THE PROMISE THAT CHANGES IN INTERNAL DESIGN AND ALTERNATE MATERIALS HOLD FOR IMPROVED PRODUCTION AND ENHANCED QUALITY. THE FOCUS IS ON GRINDING SPINDLES