Cobalt Drill Bits vs High Speed Steel (HSS) drill bits – What is the Difference?
Some people talk about cobalt drill bits and HSS drill bits like they were the same thing, and others say they are completely different. This article will explain the differences between HSS and cobalt drill bits, and what those differences actually mean to you.
What are HSS drill bits?
HSS drill bits (High Speed Steel drill bits) are the most common type of drill bits on the market today. They come in a huge variety of types, shapes and materials, and each is designed to do one or more jobs particularly well.
HSS drill bits were invented to cut into steel and other metals, but they are also very effective at cutting other materials, such as wood or plastic. There are 5 kinds of HSS drill bits, one of which we’ll look at in more detail below.
- HSS-R bits – HSS-R drill buts are roll-forged steel. This is the least expensive manufacturing technique, and HSS-R bits are generally the cheapest to buy. All the other manufacturing technique sin use create a more expensive, more specialised bit.
- HSS-G Bits – HSS-G bits are created by grinding. This is a more expensive process than rolling, but it tends to deliver a stronger bit that holds its edge longer.
- HSS-TiN – HSS-TiN bits have a super-strong coating of titanium nitride (TiN). This coating also reduces the amount of friction the bit experiences, preventing it from getting as hot when used to cut hard materials, TiN bits tend to eb yellowish in colour.
- HSS Jobber – ‘Jobber’ bits can be any of the other types, but conform to a standard length. This length is generally good for both hand-held and bench drills.
- HSS-CO – HSS-Cobalt drill bits are made if a cobalt-infused steel which is stronger, more heat resistant and yet also more brittle than standard steel formulations. They are generally more expensive but more effective than other types of HSS drill bits.
What are cobalt drill bits good for?
Cobalt drill bits Are the best of the best for cutting into hardened metals like steel. Most have between 5% and 8% cobalt. Because pure cobalt has such a high melting point (1495OC), it conveys a higher melting point to the steel. That means you can push it farther and harder when cutting metals, and it won’t soften or deform.
In the end, you can use cobalt drill bits in faster drills than standard HSS bits as well. There are many situations where you could use a cobalt bit dry when you would need to use cutting fluid to cool another type of HSS bit, for example.
Even under heavy use, the exceptional hardness of cobalt drill bits mean they maintain the sharpness of their edge longer. They even resit rusting longer than most other types of HSS bits, so tey are easier to store.
