Drill bits are an essential element found in anyone’s toolkit. They are a common accessory for drills and come in a variety of different sizes and shapes. So if you’ve ever wondered about all the different types of drill bits available and what applications they’re each best suited for, you’ve come to the right place.
Using the wrong type of drill bit for a given material or application could permanently damage your drill. So, knowing the difference between each type of drill bit and what projects they’re best for will not only help you achieve optimal drilling results but also protect the health of your tool.
As you continue reading through this guide, we’ll take a look at the different types of drill bits and explain what applications they are each designed for so you can choose the right tool for the job.
What is a Drill Bit?
Let’s start off with a quick explanation of what a drill bit is. It is a drill accessory that creates holes in different materials. Using a drill, the drill bit rotates and cuts into the desired material, removing a precise portion of the material to form a hole.
Drill bits come in a variety of diameters, shapes, and materials, which are each suited to specific applications.
What are Drill Bits Used For?
The purpose of using a drill bit will vary from project to project, and they are commonly used in construction, woodworking, metalworking, masonry, and electrical work.
For instance, drill bits can be used to bore a hole through a wall to run electrical wire or plumbing elements through a home. Or, drill bits can create a hole for a fastener to join two components together. These are just a few of the many applications of drill bits, and there is a unique type of drill bit for each specific use case.
Since drill bits are designed for specific applications, they are often sold individually or in multi-sized sets so you can select the proper bits for a given project. When you are selecting what type of drill bit to use, make sure you consider the material it’s made of, what you’re drilling into, and what type of drill bit your project requires for best results.
Drill Bit Types
Now, we can review the various types of drill bits that are out there. As you will find, there are more than a dozen different types of drill bits, each suited for different materials and applications.
Twist Drill Bit
A twist drill bit, or fluted bit, is considered the most common type of drill bit. This type of bit is highly versatile as it can be used for a number of purposes, and comes in a range of diameters. A few other drill bit types that we’ll discuss below are variations of the basic twist drill bit.
Twist drill bits have a cylindrical, twisting shape, which gives it its name. The twisting design of the bit creates grooves along the body, which end in a point. Together, the pointed end helps puncture the desired material during drilling and the twisted grooves can then cut through the material and remove any excess material that is produced in the process.
Brad-Point Drill Bit
The brad-point drill is similar to the design of the twist drill bit, though it is specifically designed for drilling holes into wood.
When looking at a Brad-point drill bit, you’ll notice the sharp centered point at the tip, which allows for accurate drilling. This feature makes it well-suited for woodworking projects, which typically require precision. The cutting spurs on either side of the centered point cut into the surface of the wood as the bit rotates for a clean entry and exit hole.
Just like with the twist drill bit, the grooves present along the body of a Brad-point drill bit work to remove excess material, typically wood, from the bored hole.
Auger Drill Bit
The auger drill bit is another type of bit that is dedicated to boring into wood. The long spiral and fluted shape resembles an auger or corkscrew, and they can come in longer lengths than other bit types.
These types of drill bits help drill clean, deep holes into materials and are typically used in woodworking. Similar to how the Brad-point bit works, the two fluted sides help work through wood quickly.
Self-Feed Drill Bit
The self-feed drill bit is one of the more unique options available. Like many of the others we are highlighting here, it is best used for quick and efficient drilling into wood. More specifically, it is designed for creating holes of a larger diameter than most of the other types of drill bits.
The unique design of self-feed drill bits makes them ideal for boring into thick pieces of lumber. The cutting edge of the bit features a sawtooth pattern compared to the fluted shaft of the other bits we’ve discussed so far.
Though much wider than other bits, the pilot point at the center of the self-feed drill bit helps provide more precision while drilling.
Installer Drill Bit
Moving away from woodworking, installer drill bits are commonly used in electrical work, as they are well-suited to tasks like installing electrical conduits, cables, and wiring in hard-to-reach locations.
They have a specific twist design at the end of the shaft for efficient drilling and typically have a long length to reach deep into various materials. Once the bit has been used to drill a hole, the wire can then be threaded through the small hole at the end of the bit and run back through the bored hole for installation.
Spade Bit
The spade, or paddle, bit is built for boring holes of a wider diameter into various materials, most often in wood. As such, they come in a variety of various sizes for clean and efficient drilling of holes. These types of drill bits are commonly used in a wide variety of construction and woodworking projects.
The spade bit is characterized by the flat design of the bit. But, you will also notice the pointed edge that helps keep the bit steady and in place for neat and precise drilling.
Forstner Drill Bit
The Forstner bit is most similar to the self-feed bit that we’ve already described. Given its unique design, it’s best for boring, clean, and smooth flat-bottomed holes in wood, which is useful when you want to join two pieces of wood together with a dowel.
Again, the pointed center of the bit allows for precise and accurate drilling, and the serrated edge of the bit helps to prevent splintering and results in a smoother-edged hole with a clean exit.
Hole Saw
These bits are used to drill large holes into different types of materials like wood, plastic, or metal, depending on the specific design. Hole saws are typically used when you need to create holes of a substantial size, like for certain types of plumbing, electrical work, or construction.
The circular shape of the hole saw bit creates a plug of the waste material rather than shavings, which may be useful to reserve in certain circumstances or projects. The material that the hole saw edge is made from makes it more or less conducive for cutting through specific materials effectively. For instance, a hole saw that has a carbide edge is often better used on tougher materials like masonry or ceramic.
In order to use it with a drill, there are a few other components you’ll need to have, including an arbor or mandrel to attach it to the drill. If the hole saw doesn’t already have a pilot bit, this can be added to help steady and center the hole saw.
Countersink Drill Bit
A countersink drill bit, sometimes called a screw pilot bit, is used to drill in a conical shape so fasteners can sit flush with the surface of the material they’re being drilled into. They are highly versatile drill bits and can be adjusted at various angles to match different screw head types.
Plug Cutter
Another common type of drill bit is a plug cutter bit, which can be used to create wooden dowels or plugs from various materials, often wood. These types of drill bits can come in a variety of different diameter sizes to fit in different-sized holes.
The created plugs are often used to conceal fasteners in woodworking projects for a more aesthetically pleasing appearance.
Step Drill Bit
Step drill bits, or unibits, are unique in that they can drill holes of various sizes without having to change the bit. Their cone, or “stepped” profile results in progressively larger diameters, which are commonly used in metalworking and electrical applications.
Tile Drill Bit
Tile drill bits are specialty bits that are designed to cut through delicate and brittle materials including ceramic tiles, porcelain, and glass without cracking or shattering the material. Tile drill bits are commonly made with a hard tungsten or carbide tip with a smooth, round edge to minimize potential damage to the drilled material.
Masonry Drill Bit
As the name might suggest, this type of drill bit is designed for drilling into tough and dense materials like brick, masonry, mortar, or concrete. As you can see, many masonry drill bits have a wider tip, which allows for quick drilling even through tougher materials like brick. But, they still have the spiral or fluted shaft design you’ll find with many other types of bits to help remove debris during drilling.
These drill bits are often made from extremely durable metal to withstand the abrasiveness of drilling through masonry, concrete, and other similar materials. This unique feature makes them much better equipped for drilling through masonry than other types of bits.
Drill Bit Materials
Just as there are a variety of drill bits available, they can also be made from a number of different materials. The choice of drill bit material can influence its performance and the types of materials it can effectively drill. Here are some of the common materials that drill bits can be made from:
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High-speed steel (HSS): high-speed steel drill bits are highly durable, versatile, and heat-resistant; suited to drilling in many materials, including wood, plastic, soft metal, and certain types of masonry
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Cobalt steel: similar to HSS drill bits, but with higher cobalt content; they are more heat-resistant than HSS drill bits, and are best for drilling into other types of metal
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Carbide-tipped drill bits: carbide drill bits are extremely hard and durable; perfect for drilling through tough and dense materials like concrete, masonry, and hard metals while retaining sharpness
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High-carbon steel: made from a high-carbon content steel alloy, these drill bits are known for their versatility and affordability, though they aren’t as heat-resistant or as durable as other drill bits made from other materials
Drill Bit Finishes
Aside from the different materials that make up drill bits, they can also come with a number of finishes and coatings for enhanced performance. Most commonly, special coatings are added to extend the life of drill bits or make them more heat-resistant. Let’s review some of the most popular drill bit finishes you may come across:
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Titanium nitride: a gold-color coating that’s added to reduce friction while drilling, helping bits stay sharper longer and be more resistant to heat; can make drill bits more expensive
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Titanium carbonitride: a gray-color coating that is even harder than titanium nitride, making it best for drilling into abrasive materials, though it can be more expensive
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Titanium aluminum nitride: a dark gray-color coating that is added for drill bits that will be used in high-heat applications and drilling into heavy metals
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Crushed diamond: a coating made from industrial-grade diamonds to make drill bits more durable and hard even when drilling into abrasive materials
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Black oxide: a coating to help make drill bits more corrosion-resistant and long-lasting
Industries For Drill Bits
To further illustrate the specific applications of each type of drill bit, here are the unique types that are best suited for woodworking, masonry, and metalworking.
Woodworking
In woodworking, there are many types of drill bits that can be utilized, with the most common one being the twist drill bit. However, auger and Brad-point drill bits are also well-suited for woodworking projects and can offer a bit more precision than standard twist bits.
These drill bits are well-suited for drilling holes of less than a one-inch diameter. But, for larger holes, spade, self-feed, and Forstner drill bits are all great choices for boring into wood. Specialty drill bits like the countersink drill bit, the plug cutter, or the step drill bit all serve their own unique purpose and are effective when drilling into wood.
Masonry
When it comes to drilling into tough surfaces like concrete, brick, mortar, and masonry, there are a few specific types of drill bits that are suitable. Certain twist bits made from the right materials and coatings can be durable enough to withstand drilling through these abrasive materials. However, specialty bits like masonry or tile drill bits are often the best choice that are designed for use in these projects.
Metalworking
A number of drill bits can be utilized in metalworking. For instance, a twist bit made from HSS is highly heat-resistant, making it a great choice for drilling into metal. The metal strands of waste produced when using this type of drill bit are easier to clean up than metal shavings or chunks that other types of drill bits might produce.
A step bit can also be useful in metalworking when you’re dealing with a thin piece or need to widen an existing hole. Like with woodworking, if you need to produce a metal hole that is wider than one inch in diameter, the job will likely require a hole saw.