General description Made of special steel with heat treatment, this set of 6 square hole drill bits features a high hardness of HRC 48-50, an elongated core, and high concentricity for long-lasting use. These professional drill bits are ideal for construction, installation, renovation, and the decoration industry. Technical specifications Slot Diameters: 1/4 inch (6.4 mm), 5/16 inch (8 mm), 3/8 inch (9.5 mm), 1/2 inch (12.7 mm), 9/16 inch (14 mm), 5/8 inch (16 mm) Weight per bit: 1/4 inch (106 g), 5/16 inch (131 g), 3/8 inch (154 g), 1/2 inch (195 g), 9/16 inch (214 g), 5/8 inch (222 g) Total weight: approximately 1215 g Usage These drill bits are great for mortising, chiseling, and woodworking. To punch square holes, use them with an electric drill, hammer, or other compatible tools. Other information Double action assortment: You get a double effect when using them with a plug-in and tenon machine.