3-Piece Titanium Step Cone Drill Bit Set - HSS High-Speed Steel Hole Cutter Kit with Storage Pouch - Perfect for Metal, Wood & Plastic Drilling - DIY & Professional Use

How to use High Speed Steel Titanium Drill spiral grooved multiple hole step drill bit 1.Please mark the cross to confirm the center of the hole. 2.Use low speed to drill holes through the spiral grooves. 3.Then speed up the spiral grooves of the spiral grooves to avoid the running deviation of the ladder. 4.No need to replace bits when a new sized hole needs drilled. Package includes: 5 step drill bit: 4-12 mm (4 mm, 6 mm, 8 mm, 10 mm, 12 mm) 9 step drill bit: 4-20 mm (4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm ) 10 step drill bit: 3-12 mm (3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm) Note: During the operation, water must be injected to cool the drill bit. During the operation, the high-temperature smoke is easy to be annealed, to avoid reducing the service life of the drill bit. When in use, the metal thickness must not exceed 3 mm. Please keep it properly preserved. Avoid falling the bits from a high place.