With tool technology improving dramatically, it's easy to feel like you're behind the latest improvements. What's more, differences within common tool categories can be confusing. In generations past, when a craftsman needed a hammer, he would go to the local hardware store and buy one. Today, the same craftsman might stand in front of rows of hammers and choose between hickory handles, fiberglass, or carbon fiber. Should he get a titanium or steel head and why? The incredible market mechanisms that serve our needs also pose problems. What about multiple types of drill bits? We could talk about the best bits, but let's talk about the difference between black oxide, titanium, and cobalt bits.
All the different types of drill bits in these categories are based on high speed steel (HSS), which is the name you often see when reading about drill bits. However, the treatments these HSS bits receive turn them into black oxide, titanium or cobalt, making a dramatic difference in performance, intended use and lifespan. Knowing the difference can help you avoid wasting money and using the wrong bits for the wrong material.
Titanium drills are high-speed steel drills coated with titanium nitride (TiN) using a process similar to electroplating. TiN is a ceramic material that increases the surface hardness of the bit and provides a thermal barrier by reducing friction. This results in increased productivity, corrosion resistance and 3 to 6 times longer tool life. Titanium bits are suitable for drilling iron, steel, aluminum, magnesium and wood.
Titanium drill bits are great for general purpose drilling in a production environment because they drill quickly. The TiN coating also helps chips flow through the flutes, which is useful because some materials, such as aluminum, stick to the drill bit more easily than others. However, once the tip becomes dull, it cannot regain its cutting edge without recoating it with titanium nitride. It often makes more sense to replace rather than repaint. So even though they are harder than cobalt, their edges are only the depth of the surface.
Cobalt Bits – Not Coated
High speed steel alloyed with 5-8% cobalt to make cobalt drill bits. These are the best metal drill bits because they are highly resistant to the high amounts of heat generated when drilling in highly abrasive and/or hard materials such as treated stainless steel, titanium, and cast iron. Unlike TiN coatings, cobalt is present throughout the material, making it ideal for high-volume work.
Most professionals do not use cobalt drills for general use due to their durability and cost. The extra hardness allows manufacturers to reduce the percentage of the overall thickness of the grooves, thereby increasing the strength of the drill. You can also sharpen them without losing the cut. Cobalt drills cost more than TiN or black oxide drills, but many professionals find their toughness valuable.
Black Oxide Drill Bits – Basic and Cheap
Manufacturers heat HSS bits to 950 degrees Fahrenheit to create a black oxide surface that resists rust and corrosion. This reduces friction between the drill bit and workpiece, which speeds up the drilling process. Bits made with black oxide coating are suitable for steel, copper, aluminum, brass, oak, maple, MDF, pine, PVC, polycarbonate, acrylic, ABS, nylon and composite materials.
Black oxide drill bits last 50% longer than standard HSS drill bits. They offer exceptional durability and speed. Many professionals have found that they have used it for years and consider black oxide drill bits to be the best general purpose drill bits you can buy.
wrap it up
We hope we have been able to help you understand the difference between black oxide, titanium and cobalt drill bits. Do you have some professional tips of your own on how to choose a drill bit? Add them in the comments below, or sound off on Facebook, Twitter, and Instagram.