Excellent Quality This square drill is made of high-speed steel, sturdy and practical, with high efficiency. Heat-treated cutting edge provides high hardness, continuous blade design for fast cuts. High-Quality Design The drill guide design provides effective protection against tearing at the start of use. No lag, and the saw blade automatically unloads from the top of the hole on both sides, preventing blockage. Labor Saving and Precision Reduces workload for construction workers, increases construction speed, and lowers costs in construction, installation, renovation, and decoration projects. Wide Range of Uses Ideal for drilling square holes in wood using a mortiser or mortising attachment. Designed primarily for woodworking applications. Not suitable for use with electric drills or bench drills. Wide Application This square hole drill bit is suitable for various wood materials including MDF, plastic, particle board, softwood, pine, and basswood. Note: Not suitable for metal, glass, concrete, or plasterboard. Scientific Matching and Multiple Sizes 7-piece set with different slot diameters to meet various needs. Each drill bit is precision-engineered for accurate hole drilling. Individually packaged in durable plastic cases for easy storage and maintenance. This comprehensive set of long square drill bits in multiple sizes meets most standard requirements. Enables precise and efficient square hole drilling. Mortise and Tenon Functionality Combination of square hole drilling with a center outer sleeve ensures clean, accurate results. Use with appropriate power mortising machines to achieve required square holes. Alloy Drill Construction Forged from alloy steel with overall heat treatment for high hardness and extended service life. Drill Guide Design Cutting edge is aligned on the same plane to enhance strength and prevent splitting during initial use. Chip Flute Design Standard chip flute allows efficient chip removal from one side, improving drilling efficiency. Universal Shank Type Round shank design ensures secure and stable clamping. Compatible with square hole machines and mortising machines.