The 2-Bladed Underreamer is used to drill obstructions such as cement, sand, scale and bridge plugs below a restriction. This tool is designed to work with a motor or threaded tubing. The Underreamer blades are actuated by pump pressure, forcing a piston to expand the blades into their operating position. The blades are continuously cleaned as fluid flows through the tool. Once the pump is shut off, the blades can retract back into the body. This design utilizes a fully contained pivot pin that secures the blades with greater reliability than other designs.