Feature:1. With overall heat treatment, making it has high hardness and long service life.2. U‑shaped chip grooves, facilitate the discharge of wood chips and improve drilling efficiency.3. The force is in a plane, which is effectively protected and can avoid the situation of bursting at the beginning.4. Universal shank type, the drill tail adopts a roun designed, which makes the clamping more stable.5. Wide application, suitable for square hole drills and square tenon machines.Specification:Condition: 100% Brand NewItem Type: Square Hole Drill BitsMaterial: Bearing SteelColor: As picture shownUses: Suitable for wood products such as density board, medium fiber board, particle board, wood, etc., suitable for square hole drills and square tenon machinesSpecification: 1/4, 5/16, 3/8, 1/2SpecificationHole SizeShank DiameterGrooves DepthTotal Length 1/46.4mm /0.3in4mm / 0.2in45mm/ 1.8in180mm / 7.1in 5/168mm / 0.3in5.5mm / 0.2in60mm / 2.4in180mm / 7.1in 3/89.5mm / 0.4in9.5mm / 0.4in60mm / 2.4in210mm / 8.3in 1/212.7mm / 0.5in10mm / 0.4in60mm / 2.4in210mm / 8.3in Package List:4 x Square Hole Drill BitsNote:Cannot be used on metal, concrete, glass and gypsum board.