Product specifications Sizes: 6.4 mm, 8 mm, 9.5 mm, 12.7 mm (fourpiece set) Material: 4241 speed steel Package includes: 4 pieces Key benefits — why you need this set Faster, cleaner square mortises: the matched inner cutter and outer sleeve produce accurate square holes more quickly than hand chiseling. Lower labor and installation costs: reduces manual effort and speeds up repetitive mortising work for construction, installation, renovation, and cabinetry. Durable performance: 4241 speed steel provides good wear resistance and maintains cutting edge for longer, improving tool life and reducing replacement frequency. Function and compatibility Designed specifically for making square holes (mortises) in wood. Requires a mortiseandtenon machine (mortiser) or dedicated squarehole drilling machine. Not compatible with a standard electric drill. Each square hole is formed by the inner cutter (chisel) and the outer sleeve working together; the cutter removes material inside the sleeve to produce a true square profile. Performance and handling Precise fit between inner cutter and outer sleeve delivers consistent, tighttolerance results suitable for joinery and furniture work. speed steel construction balances toughness and edge retention for efficient cutting in common woodworking materials. Use with the correct mortising machine settings (feed rate and rotation) for life and finish quality. Practical applications (use scenarios) Furniture making: cutting mortises for tenons on table frames, chairs, and cabinet carcasses. Door and window work: creating hinge pockets, lock mortises, and frame joinery during installation or renovation. Carpentry and finish carpentry: producing consistent mortises for stair joinery, trim work, and builtin cabinetry. What to know before you This set contains four sizes (6.4, 8, 9.5, 12.7 mm); confirm the sizes match your mortise dimensions and tenon layout. Do not attempt to use these square hole drills in an ordinary handheld electric drill—use a mortiser or dedicated squarehole drill press. Regular inspection and sharpening of the inner cutters will maintain cutting performance and extend tool life. Package contents 4 x square hole drill pieces (6.4 mm, 8 mm, 9.5 mm, 12.7 mm), 4241 speed steel