TJR® HSS-E M35 Cobalt Step Drill Bit Set, 3 Pcs, 2-fluted Spiral Grooved with 29 Step (4-32mm) Sizes Total for Faster Drilling in Stainless Steel, Alloy steel, Non-ferrous metals, Wood, PlasticsThe TJR HSS E M35 Cobalt Step Drill Set is an essential tool for anyone who works with tough materials like stainless steel, alloy steel, titanium, and more. Made from high speed steel (HSS E M35) with a cobalt alloy, these drill bits offer superior hardness, heat resistance, and durability. The addition of cobalt improves the toughness and wear resistance, making them ideal for high speed drilling operations, especially when drilling under high loads