Product Name: Full Grinding Woodworking Set Materials Quality: 50 steel manufacturing Specifications: (5 piece set) 64-127mm (eight piece set) 19-64mm (13-piece set) 19-127mm Use Way: Installed in ordinary hand drills, impact drills, rechargeable drills, flat drills and other machines Using method: Cutting wood with knife--It must be fixed well, and it must be at a right angle of 90 degrees to the opening. When positioning When you drill through, please wait for a while, and then slowly drill through. During operation, such as If there is abnormal or unsatisfactory cutting, please stop working and exit the hole opener to clean up After the end and internal control, you can work again. Note: Do not use Metal items such as steel bars