| http://www.w3.org/ns/prov#value | - Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.SUMMARY OF THE INVENTIONIn one aspect of the present invention, this is accomplished by providing a chuck and drill bit combination for insertion into a front end of a casing member of a percussive, down the hole drill for selectively engaging and disengaging said chuckand drill bit during drilling
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