Cobalt (Steel Blend)Ĭobalt drill bits are made from an alloy of 5% – 8% cobalt.

You’ll want to look elsewhere for concrete/masonry and you’re better off using your inexpensive black oxide bits for plastics and composites. Titanium is a good choice for metal and wood-drilling. Another is that you’ll need to pay more for these. One of the downsides is that the titanium nitride is just a coating and you lose the benefits as the coating wears off the cutting edges. Titanium drill bits tend to drill faster than black oxide and chips move through the flutes better. The result is a drill bit that lasts longer than black oxide. The added benefit comes from increasing the surface hardness and creating a thermal barrier that reduces heat buildup. Titanium nitride is a coating you can use instead of black oxide that does the same job of resisting corrosion and friction. Also, don’t expect to cut through metal other than softer steels under 1/8-inch in thickness. The downsides are that they don’t stay sharp as long as some of the other twist bit options out there and you lose the benefits as the coating wears off the cutting edges. It’s a good general-purpose design that’s suitable for wood, softer metal, plastics, and composites that doesn’t cost an arm and a leg. What are the best drill bits made of? Black Oxide (Coating)īlack oxide is a coating over the steel drill bit to add corrosion resistance and reduce friction between the bit and workpiece. On our web site we have divided these into two categories: Drill Bits - Normally used with hand held drills or drill presses fitted with standard chucks.

The larger-size bits have blunt tips and are used for hole enlarging.ĭrill bits are generally classified as Twist Drill, Counterbore, Countersink, Flat Bottom Boring, and Specialty. Some bits come to a point and are thus self-starting. Due to its design, a single bit can be used for drilling a wide range of hole sizes. A unibit (often called a step drill bit) is a roughly conical bit with a stairstep profile.

Drill bits