Abstract: A reinforced lightweight metal piston having fibers within the piston crown to reinforce the crown surface to improve the thermal properties and wear resistance of the crown surface. The reinforcing fibers are embedded in the piston metal using a pressure casting process used to manufacture the piston. The fibers are selected from the group of aluminum silicate, alumina, silicon carbide, silicon nitride, boron, boron carbide and graphite. The fibers can be orientated in the preform in several various directions. The wear resistance of the piston crown can be further increased by the addition of a ferrous heat plug. The fiber reinforced portion is located around the heat plug and provides improved physical and mechanical properties of the piston crown to reduce cracking of the crown around the heat plug and loosening of the heat plug due to metal creep.

Abstract: A method for manufacturing a masonry drill is disclosed. The drill has an axially elongated body which is made from a die cast material and has one or more spiral grooves cast in its exterior surface substantially along its length. A hard insert is embedded in the leading end of the body. The insert is formed with sides having generally planar side portions, a top chisel edge, and a bottom edge. The insert preferably has projections for interlocking with the body. Each projection extends the greatest distance from the plane of the side portions near the bottom edge of the insert. The insert is held in place by casting the body around it so that the body substantially surrounds the projection, and especially entirely covers the portion of the projection nearest the chisel edge. As the die cast material of the body cools following the casting operation, it contracts around the insert to securely hold the insert in place. An extremely economical yet rugged drill is thus formed.

Abstract: A masonry drill and method for its manufacture are disclosed. The drill has an axially elongated body which is made from a die cast material and has one or more spiral grooves cast in its exterior surface substantially along its length. A hard insert is embedded in the leading end of the body. The insert is formed with sides having generally planar side portions, a top chisel edge, and a bottom edge. The insert preferably has means for interlocking with the body, the interlocking means preferably comprising a projection extending from the plane of each of the side portions. Each projection extends the greatest distance from the plane of the side portions near the bottom edge of the insert. The insert is held in place by casting the body around it so that the body substantially surrounds the projection, and especially entirely covers the portion of the projection nearest the chisel edge.