Description Step Drill Bit, Metal Countersink Drill Bit 4PCS 4-12/20/32mm Step Drill Bit Steel Countersink Conical Triangle Drill with Titanium Coating Screwdriver Drill Bit for Steel/Wood/Brass/Plastic/PVC [Sturdy and Rustproof]Made of high quality HSS, it cuts through thin materials quickly. HSS provides extreme durability, and the drill bits are rustproof. At the same time, our drill bit is suitable with electric screwdriver [Application]Step drill bit suitable for DIY, home and construction. It is very suitable for drilling holes in a variety of materials like steel/brass/wooden/plastic/thin iron plate/aluminum materials/insulation plate/PVC plate, etc. Only suitable for ordinary aluminum, iron and steel plates (thickness can not exceed 4mm, hardness is less than 25HRC), not for stainless steel [Twist Drill Bit]With 4mm 6542 Twist Drill Bit can pre-drill the materials, which makes the step drill bit less easily damaged than the ordinary step drill bit. Note: Oil the step bits before each use to maximize life. 3PCS Step Drill Bits (4-12mm/20mm/32mm) with 4mm Twist Drill Bit - High-quality hardened steel high-speed steel auger - Liner uses titanium alloy coating to reduce friction and heat - Suitable for DIY, home and general construction/engineering. Can be used for wood, sheet metal, steel and other surfaces Note --- Before use, it is necessary to install a fixed clamping hexagonal rod to prevent the occurrence of swinging and tension in the groove, etc., to avoid the risk of cracking. Chute and so on -----Step drill bits suitable for DIY, home and construction. The material is only suitable for ordinary aluminum, iron and steel plate Product specifications: Material: Steel Length: 4-12mm length: about 7.2cm 4-20mm length: about 7.2cm 4-32mm length: about 10.2cm 4mm twist drill bit Length: about 7.2cm Size: 4-32mm (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm) 4-20mm (4mm , 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm) 4-12mm (4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm , 12mm)