Tru-Cut PC3500 3-1/2 Taper Fit One-Piece Carbide Tipped Percussion Core Bits are thick wall core drills. The Thickwall core bits provide a cost effective way for heavy duty drilling of large holes. Sizes range from 1-1/2-Inch to 6-Inch and used a Hex starter bit. These percussion core drills feature a taper fit. The shank and core drill will permanently become one-Piece during use.