Abstract: Disclosed herein is a rock bit having a quick change connection for use with an auger drilling machine. The quick change connection comprises a female connection extending upwardly from the body of a conventional rock bit. The connection has polygonal sides that mate with matching surfaces of a male connection secured to a kelly. A pin extends through mating holes in the female and male connections for fastening. Thus the male connection is axially releasable from the female connection by removing the pin. This permits convenient change between the auger drilling system and the rock bit drilling system.

Abstract: Disclosed herein is a rotary-percussion earth boring bit that has an improved geometric configuration to minimize fatigue failures and reduce manufacturing costs. The body of the bit is formed of a single mass of metal through which extends a single air course, without intermediate deflection or intersection, from a central portion of the upper, anvil surface to the face of the bit. The air course intersects this face in an off-set relationship with the axis of rotation of the bit. Button type inserts are included in the face and one insert is adjacent to both the air course and the centerline of the bit.