Both cobalt and titanium drill bits are derived from high-speed steel (HSS). It’s how high-speed steel is treated that defines which type of bit it becomes.
What are HSS drill bits used for?
High-speed steel bits are commonly used when drilling hardwoods, softwoods, metal, plastics and more at high cutting speeds.
They feature improved heat resistance and durability over carbon-steel bits and as such have largely replaced them.
Cobalt Drill Bits
Popular for their tough design, cobalt drill bits are formed by alloying 5-8% cobalt with high-speed steel. The result is a drill bit capable of withstanding extremely high drilling temperatures.
What are cobalt drill bits used for?
Unlike titanium drill bits, cobalt drill bits are not intended for general use! Instead, they are designed for high resistance applications that generate a lot of heat.
These applications include drilling hard, abrasive materials like titanium, treated stainless steel and cast iron.
Pros & cons of cobalt drill bits
Cobalt drill bits are the go-to bit when you need to drill very hard materials. While a coated bit would wear down extremely quickly, a cobalt one will not.
Because cobalt bits aren’t coated but actually formed using the alloying process. The end product is a much more durable bit. Of course, it can still be sharpened if the bit ever goes dull!
More expensive than both titanium and black oxide drill bits, the only real downside to cobalt bits is the price.
Although they work just fine on softer materials it isn’t very cost-effective to use them as a general-purpose bit. Wearing them down on tasks that can be done with a cheaper bit will get costly!
Titanium Drill Bits
Titanium drill bits are high-speed steel bits that have been coated with titanium nitride.
The titanium nitride coating gives them exceptional surface hardness, corrosion resistance and friction reduction while drilling.
What are titanium drill bits used for?
The hardened titanium coated surface makes titanium bits great for repetitive, general-purpose use. Suitable materials include stainless steel, wood, iron, magnesium and aluminium.
Pros & cons of titanium drill bits
A major advantage of the titanium coating is a reduction in friction during drilling. Since reduced friction lowers the production of heat, titanium drill bits don’t degrade as quickly.
Also, in comparison to cobalt bits, titanium bits are much cheaper. So, not only are they long-lasting, but cheaper too! This makes them extremely well suited to general-purpose drilling.
Although the outer edge of a titanium drill bit is harder than cobalt, it is only skin deep due to the coating process. This means when the edge does dull, they will need to be recoated or completely replaced.
So, are titanium or cobalt drill bits better?
Unfortunately, this is not a simple yes or no answer.
The answer depends on your intended application.
If you need a drill bit for metal or generally tougher material, go for a cobalt drill bit.
Because the alloying produces a much more durable bit compared to a bit that has just been coated like titanium bits.
The alloying process also means they take longer to wear down and when they eventually do, there are various sharpening methods that can be used like a bench or angle grinder to bring the sharpness back.
Cobalt drill bits succeed where others fail and are for users who require the toughest bit money can buy.
Despite the name, at their core, a titanium bit is a high-speed steel bit with a titanium nitride exterior. Due to this manufacturing process, they are very affordable and better suited to general-purpose applications such as working with wood, plastics and soft metals. Unfortunately, when the coating wears off it turns into a regular metal drill bit without the benefits of the tin coating.
The answer to which is better comes down the application.
Are you an everyday DIYer looking for a reliable bit to work with common household materials, then go with a titanium bit. Or, maybe you’re a professional looking for a high strength bit that can stand up to harsher material found on the job site? In which case go with a cobalt drill bit!
Black Oxide Drill Bits
Black oxide bits are high-speed steel bits with additional heat treatment.
This treatment involves heating high-speed steel hss bits to 950°F, creating a distinct rust and corrosion-resistant black oxide finish.
Like titanium bits, the process reduces friction and subsequently less heat buildup during use.
This allows black oxide bits to preserve their hardness for up to 50% longer than regular high-speed steel bits.
What are black oxide drill bits used for?
Suitable for use on materials including wood (oak, pine, maple), metals (copper, brass, aluminum) plastic, alloy & carbon steels, PVC and drywall.
Pros & cons of black oxide drill bits
The unique triple tempered treatment given to black oxide bits assists in the prevention of rust and corrosion, two of the biggest determining factors in bit longevity.
This means a reduction in wear and twice the longevity over HSS. They are also more affordable than titanium, making them the best general-purpose bit available.
However, they shouldn’t be used on stainless steel due to advanced edge wear on harder surfaces.
A titanium bit is a better alternative when working with stainless steel. To prolong their lifespan make sure to remove debris after every use.
Drill Point Styles
There are two common types of drill point styles:
- 118° point – has 2 cutting edges and designed for general use in stationary drills. They are great when working with soft materials like copper, cast iron, brass, mild steel and wood. Although it does dull quicker than a 135° split point, it is easier to sharpen. It also does not self-centre, meaning a centre punch is needed.
- 135° split point – has 4 cutting edges, allowing it to drill quicker. Unlike a 118° point it does have self-centring so no centre punch is needed. Due to a thinner web, less force is needed while drilling. This results in reduced heat build-up and a longer-lasting bit. However, they are harder to sharpen. If you’re looking for drill bits for metal, choosing one with a 135° split point is your best bet!