Fits all mortising machines and drill press attachmentsSet of 4 - 1/4-Inch, 5/16-Inch, 3/8-Inch and 1/2-InchMade of the highest quality tool bearing steelHigh performance flute design geometry for superior chip extractionHardness: HRC 48~50Features: Professional wood drill bit, suitable for construction, installation, renovation, decoration industry, etc.Special steel, heat treatment, HRC48~50, high hardness, lengthened core, high concentricity.It will get double effect by matched use with mortise and tenon machine, the square hole punching needs to use electric drill, hammer & other tools.Specifications:Hardness: HRC 48~50Holder diameter: 19mm (circular)Drilling core length: 195mmSlotting flute diameter Total weight 001 1/4 inch(6.4mm) approx 150g002 5/16 inch (8mm) approx 161g003 3/8 inch (9.5mm) approx 177g004 1/2 inch (12.7mm) approx 206gShaft length:1/4 inch(6.35mm): 60mm5/16 inch(8mm):60mm3/8 inch(9.5mm):75mm1/2 inch (12.7mm):60mmColor: silver + blackMaterial: bearing steelPackage Contents: 2pcs Opening toolOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.