Cobalt drill bits are a wonder. Modern materials and manufacturing techniques have really revolutionised drill bit technology, and professionals, DIYers and hobbyists alike can now choose the perfect drill bits for any jobs. But do you know when – and when not – to use a cobalt drill bits?
1) Not All HSS Drill Bits Are Created Equal.
HSS stands for high speed steel. Cobalt drill bits are often said to fall into the HSS category, but as we’ll see in a moment they should really be treated differently. HSS drill bits are designed for drilling into metal surfaces, and today that generally means aluminium or steel. HSS drill bits therefore have to withstand the heat generated when drilling steel and other dense metals. However, they can also be used for drilling lighter materials like wood and plastic.
Cobalt drill bits are technically HSS bits, as they are steel and intended for use in high speed drills. However, most HSS drill bits have a surface coating that does the ‘heavy lifting’, whereas cobalt drill bits are made of an allow of around 5% cobalt through-and-through. By making cobalt allot steel, the manufacturers increase the melting point of cobalt drill bits dramatically.
In the end, cobalt drill bits are more like ultra-HSS bits, as they can be used at higher speeds than just about any other HSS but on the market, and will retain their edge longer. They don’t need to be left to cool as long between uses, either.
2) Cobalt Drill Bits Are What You Need To Cut Hardened Metals
For your own safety, to say nothing of your productivity, you really need to select the right drill bit for the job. If you use a lesser but to cut steel, you might get the job done. Bit it will take more time, and the bit could easily overheat, bind in the hole and shatter, spraying sharp fragments of overheated steel uncomfortably close to your hands and face!
These drill bits were designed to cut abrasive materials and hardened metals. They are prefect not just for steel and stainless steel but also bronze, cast iron and even titanium. They are really the only drill bit you should use to drill into a weld seam.
3) They Are Expensive, Because They’re Worth It
If used properly, the cutting edges on cobalt drill bits will last substantially longer than the edges on other kinds of bits used for the same job, even other HSS drill bits. This type of drill bit are resistant to rust and corrosion – important factors when the metal can get red-hot in use.
However, cobalt drill bits can be brittle compared to other HSS bits. Don’t drop them, and don’t apply torsion or sideways pressure when you’re drilling.