The spindle carriage is reciprocated along the ways on recirculating roller bearings which provide smooth, friction free motion under any load. To obtain maximum positive control of the stroke, this assembly is reciprocated by a heavy-duty hydraulic cylinder attached directly to the head.
Controlled expansion of the abrasives in the tool includes a rapid initial-expand feature. The abrasives are expanded at an accelerated rate until they contact the bore surface; at that point, stone expansion in immediately slowed to a pre-determined feed.
Solenoid-controlled directional valves meet ISO standards (picture below).