Help me translate it If the feed rate is chosen as, say, one-third of the wheel width, then only the outer third of the wheel on each side will be cutting, as direction of feed is alternately reversed. The middle third of the wheel does very little cutting and will rapidly become glazed, resulting in a convex wheel profile. If the feed rate is chosen as two-thirds of the wheel width, then the leading two-thirds of the wheel on each side will be cutting, as the direction is alternated. The effect is that the middle third of the wheel will do twice as much cutting as the outer thirds. Consequently, the wheel will wear with a slightly concave profile. Ideally the feed rate should be one-half of the wheel width, but it is better to err on the high side as the concavity is less pronounced than the convexity, and wheel glazing is to be avoided. At the end of each traverse the wheel should not be allowed to move off the end of work before a reversal is made. In view of the preferred feed rate, only the outer third of wheel width should be allowed to clear the work. Normal wheel wear will of course be accommodated by the depth of cut which is applied. This is usually between 0.01 mm and 0.04 mm for roughing and below 0.01 mm for finishing. When the work is less than the width of the wheel a technique known as plunge-cut grinding is adopted. This involves feeding the wheel into the work without any longitudinal feed being required. Unless form grinding is involved, it is advisable to oscillate the wheel by about 5 mm in the longitudinal direction to equalize wheel wear as far as possible.