A method for manufacturing type M hexaferrite powders fo the formula AFe12O19 where A is Ba, Sr, Ca, Pb or a mixture thereof. One class of the tools includes transparent components ; the image component of the tool is produced at a location in the virtual environment determined by the transparent component’s location and the point of view of the tool’s user. Further, moving the fixture along second and third axes, each extending transversely to the first axis and machining the desired pin hole contours in the piston with the cutting member. The pneumatic motor is coupled to the drive mechanism and is adapted to power the drive mechanism so that the sliding door moves in a first direction. By having dirty air to be filtered flowing both transversly and laterally, the dirt holding capacity of the filter is increased while increases in restriction are minimized. The ice cubes may be formed with a gap and a splitter may split the ice cubes at the gap.