There are more than a dozen different types of drill bits when it comes to their shape and use. However, universal twist bits are by far the most widely used ones.
These drill bits can drill into wood, plastic, and even metal. And, they are most often made out of high-speed steel (HSS). Depending on how the HSS is treated or what other elements it contains, though, the properties of the drill bit change significantly.
Below, I’ll go over three of the most common variants – black oxide, titanium, and cobalt drill bits.
Black Oxide, Titanium, and Cobalt Bits: The Basics
Even though standard, “untreated,” HSS drill bits exist, oftentimes you will be better off getting one of the higher quality, “treated,” ones. Those can perform significantly better in certain situations and can last longer.
Black Oxide Drill Bits
This finish only makes them “look cool” but its also practical since it makes the bit corrosion-resistant. It also reduces the friction that the bits generate when drilling and so they can drill a bit faster than standard bits.
You can use these drill bits with all types of wood, with plastic, as well as with metals and alloys including steel, copper, and aluminum.
Out of the three types, black oxide drill bits are the closest to the regular HSS bits. However, generally, they can last about 40% to 50% longer than comparable “untreated” HSS drill bits. Their actual performance will, of course, vary depending on the quality of the bits as well as on how you use them.
Titanium Drill Bits
Contrary to how some may interpret the name, titanium drill bits are not made of titanium. Instead, they are HSS drill bits with a titanium nitride (TiN) coating. It’s this coating with what is an extremely hard ceramic that helps them last longer, be more corrosion resistant, drill faster, and drill through strong materials.
They can be used for drilling through magnesium, steel, and even iron. Besides that, the fact that they last longer and drill faster than regular bits makes them ideal for pro use, even if drilling through softer materials like wood.
Because the performance of these bits is caused by their coating, it cannot be easily regained. It cannot be regained just by sharpening the drill like it’s possible with other types. Instead, the drill bit would need to be re-coated with TiN.
It’s generally more efficient and cheaper to just get a new bit in that case, though.
Cobalt Drill Bits
Just like titanium drill bits, cobalt drill bits are not made entirely of cobalt. Instead, they are made of an alloy of high-speed steel and cobalt. The cobalt generally makes up anywhere between 5% and 8% of the material used to produce the drill bit.
The heat resistance that adding cobalt into HSS introduces makes these drill bits ideal for drilling through hard materials like cast iron and stainless steel. The extra hardness provided by cobalt helps that as well. However, it makes the drill bits fairly easy to break.
Because the cobalt is spread evenly throughout the drill bits rather than being just a coating, the bits can be resharpened to regain their performance.
Cobalt drill bits are the most expensive of the three types talked about in this article.
Black Oxide vs. Titanium vs. Cobalt Drill Bits
Now that you know the basics of what each of the different types of bits is like, let’s take a look at how they stack against each other from a number of different angles.
While at first glance it might seem like cobalt drill bits are the highest quality ones of the three, that’s not really the case.
They might offer the best performance in some situations, but just like with other products, there are good and bad cobalt drill bits. Similarly, there are good and bad black oxide and titanium drill bits.
As such, when choosing your set, you need to – quite obviously – judge the quality within that product category. In general, the more expensive the bits are, the higher quality they are. That doesn’t mean that you’ll always need the highest quality ones, though.
For example, a Milwaukee set of titanium drill bits will generally last longer and be of higher quality than a similar set by Ryobi. Yet, if you’re not a heavy-user, you might want to go with the latter as they are considerably cheaper.
All three of the types are fine for occasional drilling of soft materials like wood and plastic. That said, cobalt and titanium drill bits might be overkill for that.
On the other hand, if you need maximum possible performance for drilling into hard materials like iron and steel than opting for either titanium – or even cobalt – drill bits is the better choice.
However, keep in mind that cobalt drill bits are easy to break and so you only want to use them in the toughest situations where black oxide or titanium bits are not enough. Another common use of cobalt drill bits is when extracting damaged screws. In that case, left-handed bits are used.
For products of a comparable level, black oxide drill bits are the cheapest of the three while cobalt drill bits are the most expensive.
However, there are many black oxide drill bits that are more expensive than some titanium and cobalt ones as well. Those are generally on the higher-end of the black oxide drill quality spectrum compared to the lower-end quality of the similarly priced titanium and cobalt drill bits.
While technically, cobalt drill bits offer the best performance and black oxide drill bits are the cheapest, it’s not as clearcut as that. Instead, you will have to consider your situation – the material you want to drill, the amount of drilling you need to get done and so on.
If all you need to drill into are softer materials like wood, then you will most likely be fine with getting a set of quality black oxide (or even simple HSS) drill bits.
On the other hand, if you need to drill into iron or steel, you should consider getting titanium or – in the most extreme cases – cobalt bits instead.