
HRC 48-50 STEEL: Made of special steel with heat treatment, these drill bits have a high hardness of HRC 48-50, elongated core and high concentricity for durable use.6 SLOT DIAMETERS: With 6 pieces per pack, these saw drill bits have different diameters of 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) and 5/8 inch (16 mm) DOUBLE ACTION ASSORTMENT: They achieve double action by combining with a mortise and tenon machine. An electric drill, hammer and other tools must be used to punch square holes. WIDELY APPLICABLE: They are great accessories for mortising, chiseling and woodworking, suitable for construction, installation, renovation, decoration in the wood industry, etc. SERVICE: We sincerely hope you have a good shopping experience in our store. If you have any questions, please feel free to contact us.Set of 6 Square Hole Drill Bits, Steel Hollow Chisel. Professional drill bit set, suitable for construction, installation, renovation,