A grinding dresser or wheel dresser is a tool to dress (slightly trim) the surface of a grinding wheel. Grinding dressers are used to return a wheel to its original round shape (to true it up), to expose fresh grains for renewed cutting action (including cleaning away clogged areas), or to make a different profile (cross-sectional shape) on the wheel's edge. Utilizing pre-determined dressing parameters will allow the wheel to be conditioned for optimum grinding performance while truing and restoring the form simultaneously. Purpose The objective of dressing the wheel is to: True the wheel by knocking abrasive particles from the wheel's surface and making the wheel concentric. This minimizes vibration and improves surface finish, eliminating the vibration of the out-of-balance wheel across the workpiece's surface. It is not unusual for grinding wheels to become out of round with use. This is partially from loaded (clogged) areas of the wheel wearing at different rates from less loaded areas. It can also be exacerbated by grinding when the wheel is not under power, such as using the work to apply braking action to the wheel to stop it from coasting. Dressing restores the roundness. When bench grinders vibrate excessively, it is usually because the wheels have worn out of round and are thus out of balance. Truing them by dressing resolves this problem. Dislodge these abrasive particles to expose fresh abrasive from the wheel's surface. Each abrasive grain is a small cutting tool; a worn grain has its edges dulled and loses its effectiveness. Exposing the fresh grains is thus a sharpening process. Glazing of the wheel is evidence of rounded grains and is noticeable by a reflective surface on the spinning wheel. Clean the wheel. If a workpiece is softer than the grade for which the wheel is designed, the abrasive particles will not be dislodged in time to present fresh, sharp grains. The wheel therefore appears to lose its edge especially as the pores between grains fill with fragments of the workpiece. The wheel is then said to be loaded. This is one reason why the selection of wheel is extremely important. Condition the wheel. Establish the optimum dressing parameters to achieve the part tolerance/finish requirements. Truing and conditioning of the wheel will happen simultaneously so understanding the wheel condition needed to achieve the desired part condition is critical. Types Star dressers — A long handled tool with a