118,537. Norton, C. H. Dec. 14, 1917. Disk apparatus.-In a grinding-machine in which the work slide is movable longitudinally and the wheel slide transversely on the base, the wheel is driven by a bolt 21 from a shaft 23 mounted in the base in such a position as to give the belt a clear and substantially vertical driving run, and a tension pulley 27 yieldingly engages the slack side of the belt. Water is supplied by a pipe 30 and is collected in a trough .32, which, to accommodate the belt, is formed with a reentrant portion 32<a>. To prevent access of water to the belt, the front of the wheel slide is fitted with a guard-plate 33 terminating in a flange 33<a>, which laps over the re-entrant portion of the trough.