General description Tungsten Carbide Tip (TCT) Forstner Bit Set is specially designed for cleanly cutting holes in end grain and fine materials. The tungsten carbide tip is ideal for drilling concealed hinges and door locks, providing precision and efficiency with its curved design that effectively removes debris. Technical specifications Material: Tungsten Carbide Tip (HRC 70) with Carbon Steel Body Sizes included: 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm Depth of cut max: 8mm for sizes 15mm to 35mm, 9mm for sizes 40mm to 60mm Total length (L1): 80mm for all sizes Shank type: Round for sizes 15mm to 35mm, Lap for sizes 40mm to 55mm, Hex for size 60mm Shank diameter: 8mm for sizes 15mm to 35mm, 9mm for sizes 40mm to 60mm Installation Must be used with an electric drill (not included). Drilling should be done in a non-reversible clockwise direction. Start at low speeds and gradually increase to high speeds. Usage Drills clean holes in both soft and hard wood.