Easy chip removal: The drill sleeve of the square hole drill bits is U-shaped, which is designed to facilitate the removal of wood chips and improve drilling efficiency. Combination set: woodworking square drill bits consist of a center core drill bit and a sharp outer drill sleeve. It needs to be used with a square hole drilling machine (square tenon machine). Material The square wood drill bits are made of carbon steel, the blade is sharp and wear-resistant, the overall heat treatment (heat treatment), high hardness and long service life. Applicable: woodworking mortising chisel drill bits are suitable for wood, including particleboard, channel wood, pine, basswood, etc. Not suitable for machining metal, glass, plastic, etc. Size:Holder diameter: 19mm (circular) ;Drilling core length: 200mm ; Slotting flute diameter: 5/16 inch (8mm), 3/8 inch (9.5mm), 1/2 inch (12.7mm). Description: color: as show The square wood drill bits are made of carbon steel forging, integral heat treatment, high hardness, longer service life, sharp and wear-resistant. It will reduce the labor intensity of construction workers, speed up construction, and reduce construction costs in construction, installation, decoration, and decoration industries. Size: Holder diameter: 19mm (round) Drilling core length: 200mm Slotting flute diameter: 5/16 inch (8mm), 3/8 inch (9.5mm), 1/2 inch (12.7mm) Note: Manual measurement, please allow slight errors on size. The colors may exist slight difference due to different screens. Package Including 3 * Square Wood Drill Bits