6PCS Square Hole Drill Bits Steel Square Hole Chisel Bits HRC48-50 Mortising Chisel Set Woodworking Carpentry Tool <ul><li>MATCHING FOR DOUBLE EFFECT: Achieve double effect through combined use with mortise and tenon machines, drilling the square hole needs to use an electric drill, hammer and other tools.</li><li>HRC 48-50 STEEL: Made of special steel with heat treatment, these drill bits have a high hardness up to HRC 48-50 and feature an elongated core and high concentricity for long use.</li><li>6 SLOT DIAMETERS: With 6 pieces per pack, these 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).</li><li>GENERAL USE: These are Excellent accessories for mortising, beveling and woodworking, suitable for construction, installation, renovation, decoration industry, etc.</li></ul> Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.