The three-point bit is designed for holing, demolition and seismic strengthening of reinforced concrete structures. The bit features sharpness and economic efficiency. The bit lineup includes the 4-inch or larger Quick Pull Type designed to address the jamming by reinforcing steel. The V-shaped groove at the edge of the chip secures a smooth work start-up. The optimum combination of the diamond grain and bond has achieved a longer service life and stable sharpness.