HRC 48-50 STEEL: Made of special steel with heat treatment, these drill bits have high hardness reaching HRC 48-50, elongated core and high concentricity for long-lasting use. 6 SLOT DIAMETER: With 6 pieces per pack, these saw bits have different diameters from 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). ASSORTMENT FOR DOUBLE ACTING: They will obtain a double effect by an assorted use with a mortise and tenon machine, punching square holes should use electric drill, hammer and other tools. WIDELY APPLICABLE: They are a great accessory for mortising, chisel and mortising. woodworking, suitable for construction, installation, renovation, decoration industry, etc. Product Description Set of 6 Square Hole Drill Bits, Steel Hollow Chisels Carpentry Tools Set Professional drill bit, suitable for construction, installation, renovation, decoration industry, etc. 6 pieces per pack with different slot diameters to meet your needs. Slot diameter / weight 1/4inch (6.4mm) / 106g 5 /16inch (8mm) / 131g 3/8inch (9.5mm) / 154g 1/2inch (12.7mm) / 195g 9/ 16inch (14mm) / 214g 5/8inch (16mm) / 222g Weight approx 1215g. STEEL HRC 48-50 Made of special steel with heat treatment, these drill bits have a high hardness reaching HRC 48-50, an elongated core and a high concentricity for long-lasting use. ASSORTMENT FOR DOUBLE EFFECT They will achieve double effect by matched use with mortise and tenon machine, punching square holes need to use electric drill, hammer and other tools. WIDELY APPLICABLE They are a great accessory for mortising, chisel and woodworking, suitable for construction, installation, renovation, decoration industry, etc.