20th November 2019

The Difference Between HSS and Cobalt Drill Bits

Sturdy, hardwearing and robust, modern metal drill bits can cut through the toughest materials with no trouble. When it comes to drilling, selecting the right tool for the job is crucial. In this article we describe the difference between High-Speed Steel (HSS) and cobalt drill bits, their strengths and weaknesses, and when you should use them.

What are HSS drill bits?

HSS bits are hardwearing and heat resistant. The large concentrations of chrome and nickel in stainless steel ensure that HSS bits are super strong and durable. HSS drill bits are capable of safely drilling through hardwood, some metals and plastic. They’re safe to operate at high speeds (RPM) and provide long-lasting performance – as long as they are maintained.

Over time, HSS drill bits can become blunt and need to be sharpened, which demands specialist tools that aren’t always available. If you’re using HSS drill bits for long periods or at high RPMs, you may need to use cutting fluid to keep the bit cool.

What are cobalt drill bits?

Cobalt bits are a combination of steel (or another alloy) mixed with a small percentage of cobalt, typically between 5 – 7%. Cobalt has a melting point of 1495°C and a boiling point of 2927°C, which makes it perfect for use at high temperatures. By combining a small amount of cobalt with another alloy, the results are incredible.

Why choose a cobalt drill bit?

Cobalt drill bits are incredibly strong. They can be operated at much higher speeds than a standard HSS drill bit. The ability to withstand heat means that cobalt bits perform for long periods without cooling or the need for cutting fluid.

They are most often used to cut through hardened and abrasive materials. Cobalt bits are able to cut through the most hardened metals, including bronze, cast iron, stainless steel and titanium. They are also able to cut through weld seams.

The cutting edge on a good quality cobalt bit should last for longer than a standard HSS bit. Like other HSS bits, they are corrosion-resistant, which means they should retain their condition in all storage and usage conditions they’re likely to experience. However, cobalt can be brittle. If your cobalt drill bits aren’t cared for properly or are dropped, they can break – which can prove costly.

Why choose a cobalt drill bit?

It’s crucial for the safety of your tools and yourself that you use the right bit for the job. You will find cobalt drill bits stocked alongside other popular choices, including titanium coated, titanium nitride and tungsten carbide bits. Each of these has its strengths and weaknesses which you should be aware of before buying.

The strength of cobalt means that drill bits are better suited to the tough challenge of cutting through steel. Cobalt bits aren’t suitable for general applications. For less intensive operations, like drilling through wood, plastic or light metals, an HSS drill bit is perfect.

HSS and cobalt drills need to be cared for and maintained to ensure they deliver consistent performance. Even the hardest wearing materials can become blunted or dulled after a period of hard work. Using the correct drilling technique improves the lifespan of any drill bit.

If you’re unsure of the equipment you need, then speak to us. At R.D. Barrett we’ve been supplying the public and the trade with high-quality tools since 1975. We’re always happy to answer any questions you might have, and give you the benefit of our experience to ensure you have the right tools to do the best job.