Best Drill Bits for Steel (Non-Hardened Carbon Steels) Milwaukee Red Helix Cobalt Drill Bits Even the best drill bits for stainless steel heat up over time, so be prepared to monitor heat buildup. Use cutting oil or similar lubricant when drilling into stainless and apply enough pressure to see a steady removal of material. With that said, stainless can actually harden up as it heats-so drilling slowly often helps you get through the material more efficiently. As a low-carbon steel, stainless steel has a natural hardness that comes without traditional hardening.ĭrilling stainless takes a strong bit-the same M42 cobalt bits we recommend above. Stainless steel alloy includes chromium (at least 10%) and nickel to make it corrosion-resistant. Hardened steel is a medium of high-carbon steel that gets heat-treated, quenched, and finally tempered. The same bits you use on hardened steel work on stainless.

We have great news for anyone looking for the best drill bits for stainless steel. With a bit less cobalt in the steel blend, it just heats up a bit more quickly. The Irwin 29-piece Cobalt M-42 Metal Index Drill Bit Set performs very similarly to the M42 set. Our best drill bits for hardened steel include the following: Best Drill Bits for Hardened Steel Drill America D/A29J-CO-PC 29-pc Cobalt SetĪlso good: Irwin 29-piece Cobalt M-35 Metal Index Drill Bit Set Using a drill press is often the best way to get quality results. However, whatever differences there are between the outer look or chemical composition, both hardened steel and stainless steel are quite difficult to drill into. Because of rust and stain resistance, good luster, and low maintenance, it has many commercial uses including cookware, cutlery, home appliances, construction fasteners, and surgical instruments. Stainless steels are steel alloys consisting of at least 10.5% chromium and there are different grades. The best drill bits for metal could be designed for these hardened steel applications or they might be optimized for speed in softer carbon steels. Much of the steel materials that we see used in mechanical engineering, energy generation, and transportation are basically hardened steel. Hardened steels are durable and can be wear-resistant, corrosion-resistant, and abrasion-resistant. The length of the drill bit has a significant influence on this, with a longer shaft being more breakable, while shorter ones are stronger.When we talk about drilling in hardened steel, we mean medium or high carbon steels typically made using a heat-treatment and tempering process. Their cobalt content makes them more brittle, which means they are prone to snapping under pressure. This isn’t to say that cobalt drill bits are without flaws. Metal becomes blunt far more quickly when it is hot, so preventing it from overheating will make a significant difference to its durability. M35 refers to 5% cobalt, whereas M42 has the highest cobalt content at 8%.Ĭobalt is strong and heat-resistant, so it is ideal for coping with the demands of drilling through iron, steel, and even titanium. These bits are graded as M35 or M42 depending on how much cobalt they contain. How to Choose the Best Cobalt Drill BitĬobalt drill bits are made of a steel alloy that contains at least 5% to 8% cobalt.

Irwin 29 piece cobalt drill bit set