Abstract: This invention is directed to a worm shaft assembly used to move corrosive and/or abrasive material such is part of an extrusion device or a press. More particularly, it relates to the construction of flights, feed quills and intermediate rings or collars for mechanical presses and extrusion devices.

Abstract: Drill bit for drilling bore holes in earth formations, the bit's cutting face provided with cutter preforms composed of polycrystalline diamonds on a tungsten carbide substrate mounted in sets from the center of the bit's face to its periphery. The first set consists of one center cutter preform. Each succeeding set has at least two preforms, all of which in a set are disposed at an equal radius from the bit's axis of rotation and, insofar as practical, are displaced from adjacent preforms in the same set by equal arcs around the axis, the cutting path of a set overlapping with that of the next set, the distance along the path between preforms for each set being not greater than about five inches. The outermost preform set is disposed in or above the junk slots.

Abstract: Drill bit for drilling bore holes in earth formations, the bit's cutting face provided with cutter preforms composed of polycrystalline diamonds on a tungsten carbide substrate mounted in sets from the center of the bit's face to its periphery. The first set consists of one cutter preform at approximately the center of the cutting face. Each succeeding set has at least two preforms, all of which in a set are disposed at an equal radius from the bit's axis of rotation and are displaced from adjacent preforms in the same set by equal arcs around the axis, the cutting path of a set overlapping with that of the next set. The next to last set of preforms is mounted from a surface coinciding with a truncated cone having a relative angle to the bit's axis of rotation of about 33.degree.; the outermost preform set is disposed in or above the junk slots, with each preform mounted extending 90.degree.