Twist drill with a pilot tip

An elongated drill bit with a longitudinal axis comprising:

• a shank at one end;
• a working end at one end;
• a flute portion between said shank and working end, said shank, working end and flute section continuous with one another;
• the working end comprises a pilot tip with a first cutting portion and a second cutting portion axially spaced from said pilot tip first cutting portion and at a terminus of said flute portion, said second cuffing portion includes a pair of cutting edges on opposing sides of said pilot tip;
• each said second cuffing edge defined by the junction of a rake face, on a surface of said flute, and a primary clearance face, adjacent said second cuffing edge;
• and a secondary clearance face continuous with said primary clearance face, said secondary clearance face on an angle of about 50° to 65° with respect to said longitudinal axis and said secondary clearance face co-planar with a rake face of said first cutting portion.

An elongated drill bit with a longitudinal axis comprising:

• a shank at one end;
• a working end at one end;
• a flute portion between said shank and working end, said shank, working end and flute section continuous with one another;
• the working end comprises a pilot tip with a first cutting portion and a second cutting portion axially spaced from said pilot tip first cutting portion, said second cuffing portion at a terminus of said flute portion, said second cuffing portion includes a pair of cuffing edges on opposing sides of said pilot tip, said second cuffing edges are substantially on a plane passing through said longitudinal axis;
• said second cuffing edge are on an angle of about 22° to about 27° from a line transverse to said longitudinal axis, said second cuffing edge is formed at the junction of a rake face defined by a surface of said flute adjacent said cutting edge, and a primary clearance face, adjacent said second cuffing edge.

An elongated drill bit with a longitudinal axis comprising:

• a shank at one end;
• a working end at one end;
• a flute portion between said shank and working end, said shank, working end and flute section continuous with one another;
• the working end comprises a pilot tip, with a first cutting portion and a second cutting portion axially spaced from said pilot tip first cuffing portion and at a terminus of said flute portion, said second cuffing portion includes a pair of cutting edges on opposing sides of said pilot tip, both said second cuffing edges are substantially on a plane passing through said longitudinal axis;
• each said second cuffing edge defined by the junction of a rake face, on a surface of said flute, and a primary clearance face, adjacent said second cutting edge;
• and
• a secondary clearance face continuous with said primary clearance face, said secondary clearance face on an angle of about 50° to 65° with respect to said longitudinal axis.