Chuck

In combination with a fluted twist drill sharpening device having a pair of spaced apart chuck receiving bearing surfaces;

• a plural-jawed chuck for gripping the fluted end of twist drills having two peripheral bearing surfaces receivable in the two bearing surfaces of the sharpening device;
• an outer tubular body having a first cylindrical rearward end and a second cylindrical forward end, the diameter of the first cylindrical end being greater than the diameter of the second end and a sloping wall section between said first and second cylindrical ends;
• a plurality of jaw members received in said tubular body, each said jaw member defining a clamping surface for gripping said drill and including a forward arcuate portion corresponding to the second cylindrical end of the tubular body, a rearward arcuate portion, and an arcuate sloping portion corresponding to the sloping portion of the tubular body;
• each said rearward arcuate portion being stepped to provide a shoulder on each jaw member;
• and means for applying a jaw closing force to said shoulder portion of each jaw, whereby the arcuate sloping portion on each of said jaw members is caused to co-act with the cylindrical sloping portion of the tubular body;
• said last named means including a bushing adapted to engage the shoulder on each jaw member, and a manually turnable knob having threaded engagement with internal threads on the rearward end of the outer tubular body and adapted to urge said bushing into chuck closing engagement with the shoulder on each jaw.