Are cobalt drill bits harder and stronger than titanium drill bits? Which one is better?
The two are very different in a few ways, but the most important difference is in the metal used to make the drill bits.
Difference Between Cobalt and Titanium Drill Bits
Both titanium and cobalt drill bits are made of high-speed steel alloy steel. The main difference between the two bits is that the titanium drill bits are high-speed steel bits with titanium nitride (TiN) coating whereas the cobalt drill bit is made of alloy steel that contains 5 to 8% of cobalt.
Cobalt drill bits are more expensive, but offer longer life, and are more resistant to heat than titanium drill bits. Cobalt drill bits are also tougher and can drill holes in the hardest metals.
Here is a quick comparison chart that explains the key differences between titanium vs cobalt drill bits.
|Titanium Bits||Cobalt Drill Bit|
|Material||High-Speed Steel with Titanium nitride coating||Alloy steel with up to 8% cobalt|
|Color||Bright gold or bluish color||Dull gold color|
|Heat Resistance||Moderate||High heat resistance|
|Wear Resistance||Very good||Excellent|
|Uses||For drilling wood, aluminum, copper, brass, mild steel, cast iron etc.||Best for drilling tough alloy steel, weld seams, hardened steel etc.|
Titanium Drill Bit
Titanium drill bits are bits made of high-speed steel with titanium nitride coating. The advantages that titanium coated bit offers over steel are, higher wear resistance, ability to withstand higher temperature, and increased durability.
There are mainly three types of titanium coating that are commonly used.
- Titanium Nitride
- Titanium Carbo-Nitriding
- Titanium Aluminum Nitride
How do these coatings differ?
Titanium Nitride (TiN): These are most commonly used entry-level coating. They can be identified by their bright gold color. Most wood drills with golden-yellow color have TiN coating. You find this coating on a wide variety of cutting tools such as countersink bits, router bits, milling cutters, etc.
Titanium Carbo-nitriding (TiCN): The TiCN coating is better than the regular titanium nitride coating. The coating is harder and offers better wear resistance.
As a result, the bluish/purple-colored TiCN coated drill bits deliver better performance than TiN.
Titanium Aluminum Nitride (TiAlN): The titanium aluminium nitride coating can withstand temperatures up to 800°C (1450°F). At high temperatures, a layer of aluminum oxide is formed and it reflects the heat back onto the drill chips. This allows you to utilize higher cutting speed and feed and increased productivity.
This grey-colored coating offers higher ductility and hence TiALN coated bits are suitable for interrupted cuts during drilling.
In short, the TiAlN coated drills provide the best results when compared to TiN, TiCN, or black oxide drill bits.
However, they are the most expensive and cannot be used for drilling aluminum due to the high content of aluminum in the coating.
In addition to the above three popular coatings, there is also AlTiN (Aluminum Titanium Nitride) which is slightly harder than TiAlN, and several other proprietary coatings.
Cobalt Drill Bits
what are cobalt drill bits? They are made of alloy steel with cobalt content. The material used here is an improvement over High-Speed Steel with an addition of 5 to 8% of cobalt in it.
Depending on the amount of cobalt content, these bits are graded differently. The grade M35 has 5% and the grade M42 has approximately 8% cobalt in the alloy.
Unlike titanium drill bits, these bits are not coated with cobalt. Instead, cobalt is added to the alloy steel itself. This has one major advantage. You can re-sharpen the cutting edges without lowering the quality of the edges.
Cobalt Drill Bit Uses
The cobalt drill bits are an excellent choice for drilling hard alloy steels, tool steels, spring steel, and aluminum alloys. They can withstand very high temperatures and still retain the sharpness of the cutting edges.
First off, both types of drill bits can be used in the drill press and cordless drills, so there is no need to purchase a special tool or drill when choosing between either material. In addition, both cobalt and titanium are similar in terms of strength and often used for the same type of jobs. The only visual difference is the color which can readily tell them apart.
Both are meant to cut through hard materials that standard drill bits such as those made of high carbon steel do not work as well. While they are both used mostly for metal, they can be used for hardwoods, too. The differences between them are relatively small but can be important depending on the application.
What is a Better Drill Bit, Titanium or Cobalt?
The most obvious difference is that titanium is used as a coating for the tip of a drill bit while cobalt is used to create the entire drill bit. The titanium drill bits usually have the coating done on the entire flute length and cutting tip that allows it to withstand wear and tear.
Because it is coated, titanium drill bits are difficult to sharpen and re-use. Because when the sharpening process removes the coating, it reduces the protection that it enjoys. Since cobalt is not coated, it can be sharpened without this concern. This can be a deciding factor in case of large size drill bits.
The main advantage of titanium drill bits is the cost. They are considerably less expensive compared to cobalt drill bits. Although as mentioned they do not sharpen as well, so they may not last as long depending on their application.
Which Drill Bit Should I Use?
Bright HSS or black oxide brad point drill bits are most commonly used for drilling wood. Both cobalt and titanium are not used often for wood. While both materials can drill through even the hardest of woods easily, they lack the brad at the tip that prevents slipping when used on wood materials.
Both are well-suited to drill through metal surfaces. This is because cobalt and titanium tend to be considerably harder compared to steel or iron. Drilling through metal is the most common use for either drill bit.
- Titanium Coated Drill Bits: For mild steel, cast iron, copper, brass, bronze etc.
- Cobalt Bits: For drilling hard tool steels, spring steel, aluminum alloys etc.
Both types can be used for some small drilling on concrete. However, they are not well suitable for concrete because they cannot withstand the higher temperatures that are generated. Instead, you should use masonry bits with carbide tips and a rotary hammer drill for the best results.
Both cobalt and titanium drill bits have their advantages and disadvantages. While cobalt is more expensive, it is easier to maintain because it can be sharpened. Titanium drill bits may not last as long depending on the material that is drilled, but they are less expensive.
Can you use cobalt drill bits in wood?
Generally, cobalt drills are recommended for drilling hard materials such as spring steel. Although you could use a cobalt drill bit to drill wood, they are expensive and hence not cost-effective. You can easily drill wood with a much cheaper black-oxide coated drill or an inexpensive bright finish HSS steel drill bit.