Whether you are a professional or simply engaging in some DIY around the house, knowing the material that your drill bits are made of as well as what each specific drill bit type is needed for what job are important factors to consider when you want to drill holes, especially into tough materials like cast iron.
Different drill bit materials work better with different surfaces, whilst different drill bit types will also work better for certain jobs.
With this in mind, we are going to be looking at some common drill bit materials and types and doing some comparisons to help you on your way to identifying which drill bit is the most appropriate for you and your hammer drill, cordless drill, or twist drill.
Let’s get started.
Drill Bit Materials
Titanium Coated
Titanium coating make for a durable and tough drill bit thanks to the hard, ceramic material from which they are made.
These kinds of bits are also useful as they allow you to run your drill at a faster level of rotations per minute without the risk of an excessive build up of heat.
There are a range of different kinds of titanium coatings available, with the following being the most common:
- Titanium Carbon Nitride (TiCN): Long lasting and highly accurate as well as more wear resistant, TiCN drill bits are incredibly strong and hard.
- Titanium Nitride (TiN): This kind of coating can increase the life span of the drill bit up to three times.
- Titanium Aluminum Nitride (TiAN): This is considered to be longer lasting one comparison to the TiN coating, with the drill bits that feature this coating having a lifespan of up to five years.
The main issue that can come about with titanium coated drill bits is that they can’t be sharpened effectively, so once they are dulled, they won’t return to the level of sharpness that they once had.
High-Speed Steel
With a good level of resistance to both wear and heat, high speed steel drill bits- otherwise known as HSS drill bits- are the most common to be found on the market due to their versatility and ability to work on a wide range of materials, including metal and wood.
Low Carbon Steel
One of the least expensive choices of a drill bit, low carbon bits are best used with certain types of plastic along with soft woods as they need to be sharpened more often than other kinds of drill bits.
High Carbon Steel
High carbon steel drill bits are an improved version of low carbon steel bits, able to be used with some particularly soft metals as well as hardwood.
Diamond
This is one of the hardest drill bit materials due to being made with polycrystalline diamond, or PCD.
PCD is made up of a layer of diamond particles that have been bonded to a support made up of carbide.
These bits are commonly used on material such as fiberglass, ceramic tiles, marble, stone, concrete and more.
Despite the tough nature of these drill bits, they can be problematic as they are susceptible to heat and will be ruined if overheated. They are also a more costly option.
Diamond drill bits tend to be used to grind material away on a micro level.
Masons drilling precision holes into materials- such as glass, stone, tile, concrete etc- tend to get the most out of diamond drill bits, particularly those working in industries that involve the drilling of abrasive materials, such as in the aerospace industry or the automotive industry.
Cobalt Coated
These drill bits are able to retain their hardness at higher temperatures in comparison to run-of-the-mill high speed steel ones. That being said, they also tend to be somewhat more brittle.
Cobalt coated drill bits are often used when it comes to drilling stainless steel as well as other, more difficult metals.
Carbide Tipped
Carbide tipped drill bits can dissipate heat and hold an edge much longer than other kinds of drill bits.
They are also incredibly hard, but can be brittle and chip easily if not used with the proper care.
Due to their ability to hold up when drilling abrasive materials, carbide tipped drill bits are frequently used in drilling processes that involve fiberglass reinforced plastic.
Zirconium Coated
Any steel and metallic drill bits are able to be coated with zirconium in order to improve their strength and reduce friction, which can improve the precise nature of the drilling.
Types Of Drill Bits
Let’s now take a look at some of the most common types of drill bits.
Twist Bits
This popular style of drill bit has a wide range of applications and a huge amount of versatility, available in all sorts of sizes and made of all kinds of materials, such as cobalt, carbon steel, high speed steel and carbide.
Shorter styles of twist drill bits are stronger, but they aren’t always the most appropriate for deep drilling.
Countersink Bits
These bits are used to countersink existing holes by creating a tapered surface hole with a center hole.
This center hole will be small enough to penetrate the material that is being drilled into, which is why these bits have tapered head fasteners that sit on the level of the material surface.
These bits will feature flat blades- either two or more- that come from the drill’s center and extends outwards to the edge.
Counterbore Bits
Designed to create a flat bottom blind hole that will conceal the fastener head and stop it from emerging above the surface material, some counterbore bits have spurs to prevent chipping or splintering.
Specialized Bits
Certain bits are specially designed for specific purposes, such as masonry drill bits, annular cutter bits, plug cutter bits and tile and glass bits.
Flat Bottom Bits
Much like counterbore bits- minus the center drill-, flat bottom bits are a type of drill bit that is able to cut flat bottom blind holes as well as drill wide thru holes, making them great for creating locks, wiring holes, and door knobs.
Drill Bit Material Comparisons
Let’s now take a look at some comparisons between the metals of the most common drill bits used for drilling holes into soft materials or even tougher materials like carbon steel.
Titanium Vs Cobalt
Titanium drill bits are stronger and tend to last longer than cobalt, making it the more effective bit for those who use a drill frequently, and especially when drilling large holes.
They are also a versatile drill bit material, able to be used with plastic, iron, steel and wood.
That being said, titanium is an expensive choice especially when it comes to drilling wood or even drilling iron.
Cobalt is much more difficult to use with hardened steel and can also be brittle, but they are an inexpensive choice for more casual drillers who want accurate drilling that cannot be offered by many other drilling materials such as solid carbine or black oxide, which is used to create carbide tips for power tools.
Cobalt is good when it comes to surface hardness and resisting heat build-up.
Carbide Vs Cobalt
In comparison to cobalt, carbide drill bits can resist heat excellently. On the other hand, cobalt is well suited to difficult metals.
Carbide is, alternatively, for use with non-ferrous heavy materials and abrasive metals, which sets them apart from cobalt bits, when it comes to working with thin metal, especially when using drill presses.
Cobalt Vs High-Speed Steel
Between these two choices, cobalt has the most resistance to wear.
That being said, it is also particularly brittle in comparison to high speed steel, which works fantastically with a handheld drill or with hammer drills to cut through even mild steel and create a pilot hole.
Despite this brittle nature, cobalt has all of the versatility of high speed steel and even more so thanks to being able to drill tougher materials.
Final Thoughts
Hopefully, you should now have all of the information that you need to decide as to which drill bit will suit your needs in the most appropriate manner!