CNC 235 H Hard machining center The CNC 235 H vertical hard machining center with horizontal workpiece spindle can be used for internal as well as external grinding. Moreover, these processes can be combined with one another as well as supplemented with other technologies such as hard turning or hard reaming. In addition to sequential machining, the machine can also be equipped for simultaneous machining, i.e. external and internal grinding at the same time or several simultaneous external grinding operations.