3Pcs High-Speed Steel Step Drill Bit Set with Automatic Spring Loaded Center Punch Power Tools Cone Titanium Coated Metal Hole Cutter 1/4″ Hex Shank Drive Quick Change 4-12mm/4-20mm/4-32mm

Step Drill Bit Set:Feature: — High speed, titanium nit-ride coated steel Replaces 28 separate drill bits Two fluted design for fast, smooth cutting. — When inject cold water while working, can effectively extend the service life of the drill bit. Recommend drilling rate of 250-250 RPM. — 1mm thickness can be operated by hand drill, 2~3mm please use bench drill. The drill must continue to cool down when it is working, and it is not easy to burn. — According to the need to process different diameter holes, you can achieve one-time processing of large holes, no need to replace the drill bit and positioning holeifications: — Shank: 1/4″ Quick Change Hex Shank — Finish: Titanium — Material: HSS (Suitable for use in the hardness below 25 degrees workpiece, such as iron plate, copper plate, aluminum plate, the thickness of the plate of step is 3mm and wood, PVC sheet, insulation boards with a thickness of 5mm(0.2 inch) or less). Can not be used to hard and brittle materials such as stainless steel, glass, tile floors, walls etc. — MEASUREMENT: 4-12 5 Steps (Diameter 4, 6, 8, 10, 12mm) 4-20 9 Steps(Diameter 4, 6, 8, 10, 12, 14, 16, 18, 20mm) 4-32 15 Steps(Diameter 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32mm) — Automatic Center Punch: 7.4 x 2.6 x 0.7 inchPackage Included: 3 x Hss Step Cone Drill Bit Titanium Hole Cutter Set 1 x Automatic Center Punch