Woodworking Square Drill Bits Set Key benefits Durable cutting edges: Made from speed steel with heat treatment (HRC 48–50) for wear resistance and longer service life. Accurate, clean holes: Lengthened core and concentricity reduce runout and wobble, giving straighter, more consistent square mortises. Ready for workshop use: A set of four common sizes covers typical mortising and joinery needs without buying individual bits. Works when paired with mortise and tenon machines or mortising attachments for efficient, repeatable results. Features Material and hardness: speed steel, heat treated to HRC 48–50 for improved edge retention and toughness. Design: Lengthened core improves rigidity; concentricity minimizes vibration and improves hole precision. Function: Specifically designed for drilling square holes in wood (mortises) using a mortising machine or a mortising attachment. Included sizes 1/4 inch (6.4 mm) 5/16 inch (8.0 mm) 3/8 inch (9.5 mm) 1/2 inch (12.7 mm) Compatibility and use Use with a mortising machine, mortising attachment, or a mortise and tenon machine. When matched correctly with these tools, the set delivers improved efficiency and cleaner mortises. Suitable for hardwoods and softwoods when used with the appropriate machine settings and sharpness maintenance. Practical applications Furniture joinery: Cut precise square mortises for tenons in table frames, chair rails, and cabinet carcasses. Door and lock fitting: Create consistent mortises for hinges, latch plates, and lock bodies. Repeated production work: Ideal for smallbatch furniture or workshop projects where consistent, repeatable mortises are required. Notes for results Use appropriate machine speeds and feed rates for the wood species. Keep bits sharp and clean for maximum life and hole quality. Confirm compatibility with your mortising machine or attachment before use. Set contents: four woodworking square drill bits in the sizes listed above.