Expandable Diameter Drill Bit

An expandable diameter drill bit, comprising:

• a first cutting blade and a second cutting blade, each cutting blade having a receiving end and a contacting end;
• a drill head body having an upper attachment portion and a lower body portion, the lower body portion defining a first blade opening and a second blade opening configured to receive respective receiving ends of respective cutting blades, the first blade opening and the second blade opening being separated by a divider;
• a first torsion spring coupled to the first cutting blade and to the drill head body;
• a second torsion spring coupled to the second cutting blade and to the drill head body;
• a blade bolt inserted transversely through the lower body portion and the first and second cutting blades, the first cutting blade and the second cutting blade being configured to pivot about the blade bolt;
• wherein the first and second torsion springs bias the blades outwardly from the drill head body in opposing directions respectively.

An expandable diameter drill bit, comprising:

• a first cutting blade and a second cutting blade, each cutting blade having a receiving end and a contacting end;
• each receiving end having a pivot shaft;
• a drill head body having an upper threaded portion and a lower body portion, the lower body portion defining:
• a first blade opening for receiving the receiving end of the first cutting blade;
• a second blade opening for receiving the receiving end of the second cutting blade;
• a bolt receiving hole on each of two opposing sides transverse the blade openings, respectively;
• and
• a first torsion spring and a second torsion spring, each spring having a helical coil, a first blade leg, and a second body leg;
• wherein:
• the first and second blades are received in respective blade openings such that respective pivot shafts correspond to respective bolt receiving holes;
• a blade bolt is inserted through respective bolt receiving holes and the pivot shafts are secured into position with a blade bolt set screw;
• the first blade leg of the first torsion spring is secured in a channel in the first cutting blade with a spring retainer bolt;
• the second body leg of the first torsion spring is inserted into the drill head body;
• the first blade leg of the second torsion spring is secured in a channel in the second cutting blade with a spring retainer bolt;
• the second body leg of the second torsion spring is inserted into the drill head body;
• the torsion springs bias the first and second blades outwardly from the drill head body;
• and
• the surface contact ends of the first and second cutting blades are coated in tungsten carbide forming a scalloped surface.