Abstract: An improved ratchet mechanism for box end wrenches or similar devices consisting of a driver ring with cam teeth on one face, a driven ring fixed to a socket member rotatably confined in the driver ring, the socket member having a wrench configuration in its interior, and a pawl ring rotatably supported on the socket member. The pawl ring has cam teeth cooperating with the driver cam teeth and the pawl ring and the driven ring have shorter interfitting teeth. The cam teeth have sufficient rise to hold the short teeth engaged when the driver ring is rotated one way, and to allow the shorter teeth to disengage when the driver ring is rotated the other way. A means for directly applying axial forces to engage the sloping faces of the cam teeth of the pawl ring and the driver ring thereby tending to encourage meshing of the driven teeth of the socket member and the driving teeth of the pawl ring in the form of a spring is positioned between the driver ring and the retainer ring.

Abstract: A method of controlling chosen geometries in sintering operations uses an insert in the preform which is to be sintered, which insert can withstand sintering temperatures without distortion, and which will not bond to the preform and thus prevent removal subsequent to sintering. In powder metal sintering, inexpensive ceramic alumina inserts satisfy these criteria. A powdered metal preform is caused to shrink onto a precisely formed ceramic insert, thereby to determine final shape accurately. An insert larger in diameter than that of the uninserted undistorted preform final diameter may be used if potential impact on geometry density is factored into its selection. An insert shape other than that of the preform undistorted final shape may be used to create final geometries different by design than those of the preform.