... be replaced by users themselves at any time for their specific conditions.Compared with ordinary hydraulic drilling rigs, Model XY-4 ... maintenance and repair.4. It has two speeds of reverse rotation for the sake of safety and labour-saving in handling ... gear 311, 574, 819, 1191 r/minReverse rotation low gear 83 r/minReverse rotation high gear251r/minWhen the prime move has a ...