Can not drill metal. The drilling process must be kept vertically and it is recommended to use a tool such as a vice to keep the materials stable so that a smooth, precisely sized hole can be obtained. Adjust the slow drilling speed until the drill is fully positioned, and then gradually accelerate the speed. The speed is controlled at 2200~2500RPM for better effect Product Size:Drilling Diameter:20mm/0.83inch, Hexagon Shank Diameter. 10mm, Drilling Depth 60mm, Overall Length 86mm Positioning drill are selected from YG8, hardness ≥ 91HRA, bending strength up to 2200N/cm², resharpenable. The shaft rod is 45 steel, After quenching, the hardness is extremely high, effectively avoiding bending of the shaft during use Uses industrial grade YG8, which extends the service life by 10 times compared to 1.3 mm thick Woodwork hole is perfect for wood, plywood, wood board, furniture, door hinges, desk, Manufacturer: JIAJUGUIFU