An earth working machine typically utilizes a digging or cutting member which employs a plurality of shanks to which teeth are attached by a variety of means including welding, bolting, and wedge-fitting.  It has been recognized that holding clamps for holding teeth to shanks provide certain advantages over current boltless teeth, as shown, for example, by U.S. Pat.  2,222,071 issued to Gustafson.  This advantage stems from different conflicting physical requirements of the cutting teeth and the holding mechanism.  The cutting point of the tooth must be formed of a hard wear-resistant material while the holding mechanism usually requires a material of at least some elasticity and/or ductility.  However, many digging members cannot take advantage of boltless clamping systems because either they have no wedge-locking system in place or they have non-standard locking grooves which are not adapted to fit the boltless holding clamp. 
As widely practiced in the art, the tooth may connect to a shank by a wedging force between a groove in the shank and a boltless tooth which includes at one end thereof, a receiving channel that is wedged upon a shank.  Such an arrangement permits quick hammer-driven changing of worn teeth but suffers the disadvantage of being expensive due the conflicting physical requirements of the cutting point of the tooth and its receiving channel.  The cutting point must be hard and rigid for good wear resistance while the receiving channel must be somewhat resilient to be wedged upon the shank. 
It is highly desireable to provide a boltless holding clamp, rather than a boltless tooth, wherein the clamp is adapted for use with an "adjustable" cutting tooth whereby a worn tip or cutting point thereof might be quickly extended and re-fastened to the shank of the digging member.  By adjustable, it is meant that the tooth may be loosened in the holding assembly, axially extended forward of the digging member of the earth working machine, and then refastened to the shank by the holding clamp.  Provision of rapid adjustment provides substantial economic benefits in reduced machine down time and reduced teeth replacement costs since a substantial portion of the expensive tooth material may be consumed, rather than discarded. 
In view of the foregoing, the present invention has as its primary objective the purpose of permitting utilization by conventional earth working equipment of a boltless holding clamp which may be frictionally engaged upon a shank thereby to enable quick changing and adjustment of a cutting tooth of hardened bar stock material. 
As stated in my above-referenced copending applications, utilization of a holding clamp advantageously permits, among other things, the use of bar stock material of constant cross section to form a cutting tooth of a hard wear-resistant material, positional adjustment of the clamped position of the cutting tooth on a shank of an earth working, digging or cutting member, absorption of vibrational loosening forces acting on the tooth, self-tightening of the tooth against the shank in response to impact loads applied to the tooth during digging and/or cutting operations.