Unxuey 3Pcs HSS Titanium Coated Step Drill Bit High Speed Steel Cobalt Nitriding Spiral Metal Drill Bit Triangle Shank Power Tools kit for Wood Metal

?Specification: ?Type:step drill ?Material:High Speed Steel ?Surface: Nitrogen treatment ?Groove Type: Spiral Groove ?Cutting materials: thin iron plate, aluminum, insulation board, PVC board that thickness is within 5mm ?Sizes: Bit 1: 4 - 12 mm in 5 steps (4, 6, 8, 10, 12mm) Bit 2: 4 - 20 mm in 9 steps (4, 6, 8, 10, 12,14, 16, 18, 20mm) Bit 3: 4 - 32 mm in 15 steps (4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 mm) ?Feature: 1.High speed, titanium nit-ride coated steel Replaces 28 separate drill bits Two fluted design for fast, smooth cutting. 2.When inject cold water while working, can effectively extend the service life of the drill bit. Recommend drilling rate of 250-250 RPM. ?Tips: 1. The use of cutting fluid can last long life. 2. The board must be smaller in thickness than the height of step drill bits. ?Package Included: 1 x 4 - 12 mm Step drill 1 x 4 - 20 mm Step drill 1 x 4 - 32 mm Step drill