Step drill set 4-12,20,30mm 3 pcs

• Includes 3 pieces • 4 mm to 12 mm in 1 mm increments • 4 mm to 22 mm in 2 mm increments • 4 mm to 35 mm in 2 mm increments • Step drill set for making holes in thin sheet metals • Titanium-nitride (TIN) coated step drill with a surface hardness that makes the tool last 4 to 5 times longer than ordinary step drill bits • Same surface reduces friction, resulting in a tool that runs cooler and effective, self-lubricates while running dry • Self-centering point • Shank size 1/4" (6.35 mm) and 3/8" (10 mm) and 1/2" (12.7mm) • For making holes in thin metal sheets • Last up to five times longer than ordinary step drills • Titanium-nitride (TIN) coating with a surface hardness • Self-lubricates while running dry