Polishing is essentially the removal of metal by the action of free abrasive grains carried to the work piece by a tool. The difference between these methods is only the degree of removal. Polishing used to bean “art”. Polishers pent many hours polishing every mold component by hand. Today, much is done mechanically, and only parts which, because of their shape, can not be finished on the mechanical polishing equipment or where the finish is exceptionally fine are done by hand. Note that in general, polishing and honing machines produce more regular( finer, flatter or cylindrical) surfaces, while hand finishing, particularly with unskilled operators, tends to increase waviness or even impart waves to a previously straight, but rough, surface. Please list several reasons for polishing.