You can’t just buy the first drill bit that you find on the shelves of your local hardware store and call it a day. Not all projects need the same type of drill bits and it’s important to choose the correct one.
There are numerous types of sizes, shapes, and designs to choose from when shopping for a drill bit. Not to mention, the wrong kind of drill bit can derail your project or even put you at risk of injury.
Because of this, it’s important that you educate yourself about the different kinds of drill bits, their differences, and what kind of surface or material a certain kind of drill bit is most suitable for.
The main reason why you want to buy the right drill bit for the material that you are going to work on is to ensure a smooth hole. The wrong bit might lead to a bad hole.
In worse cases, it might even render your project useless and you’ll have to start all over again.
Once you have a thorough understanding of the different types of drill bits, it’ll be easier for you to get on with your project.
But before you go on and choose a drill bit, you’ll have to choose a material for your project first. Once you’re done, you can go shopping for the right kind of drill bit. This is because where and how you will use the drill bit plays a huge factor when shopping for one.
As a general rule of thumb, you’ll want to buy yourself a variety of drill bit sizes for your project.
The reason for this simple: a single project can require different types of drill bits. You may also need to have a spare in case your drill bit fails or breaks.
Here’s how you can choose the right drill bit for your project.
Choosing the Right Drill Bit Based on Materials
Drill bits can be made out of many different types of metal. There isn’t a single drill bit that’s suitable for all surfaces.
Each one is designed for a specific surface or two (or a couple). Meanwhile, even if a type of drill bit can be used for a particular purpose or surface, it might not be as good compared to a drill bit built specifically for a type of material.
The different types of metal used in drill bits are:
- Low carbon steel
- High carbon steel
- High-speed steel
Learn more about the differences of each metal type below:
Low carbon steel
For smaller and beginner DIY projects, low carbon steel drill bits are ideal. They’re perfect for soft surfaces like wood.
They’re also rather affordable, which makes them perfect for when you’re drilling through something that’s not as hard as metal or hardwood.
High carbon steel
For a bit more holing strength and power compared to low carbon steel drill bits, high carbon steel drill bits are a good choice.
High carbon steel drill bits are stronger and can tolerate higher temperatures. They also don’t need frequent sharpening.
In fact, most users report to simply just replacing their high carbon steel drill bits whenever they feel like they’re no longer as sharp, since they’re not that expensive either and are arguably just as economical as low carbon steel drill bits.
If you’re drilling on materials like thin metal, as well as hardwood, you should use high carbon steel drill bits.
It’s not the same as high-speed steel which is mainly used in creating tools instead.
If you’re looking to go through hardwood and thin metal or steel faster than high carbon steel drill bits, you’ll want to take a look at carbide drill bits.
Carbide drill bits hold edges longer because they can dissipate heat faster. However, they’re also a bit more expensive and are not as durable.
You’ll want to hold off on using carbide drill bits until you’re more experienced. Otherwise, you might end up breaking the drill bit by applying too much force.
Thick steel and metal need cobalt drill bits. Other drill bit materials simply just can’t bore through them as effectively (nor as quickly).
Again, similar to carbide drill bits, cobalt drill bits are more prone to accidental damage if you apply too much force.
Although they can make quick work of thick materials like thick steel and metal, as well as stainless steel, you’ll want to use the drill as carefully as possible.
Most people won’t really need to use diamond drill bits. However, if you’re handling materials that are extremely hard to bore holes through, and yet fragile enough that it will break if you apply too much force or heat, you have no choice but to use diamond drill bits.
Diamond drill bits are ideal for materials like glass, stone, marble, fiberglass, granite, and ceramic tiles.
You can also use it to bore holes through heavy materials.
Are There Other Ways to Choose Drill Bits?
In addition to choose drill bits based on surface material, you can also choose drill bits based on coating.
Drill bits use coating for a variety of reasons. However, most of the time, drill bits are coated to make them harder, sharper, and stronger.
This makes their application more varied and extensive while also more effective.
In addition to this, coated drill bits typically last longer, are more durable, and can bore through materials much better than other types of drill bits.
The different types of coating used in drill bits are:
- Black Oxide
- Bronze Oxide
- Titanium Nitride
- Zirconium Nitride
Read on below to learn the differences of each type of coating and what their purpose is:
Black Oxide coating is typically used for Steel and Iron applications. They’re applied to drill bits to improve their tempering powering and minimize the stress applied on the surface material during the drilling process.
Black Oxide also helps lubricate the drill bit and reduce chip welding, as well as galling.
Black Oxide coated drill bits are the most economical among coated drill bits.
Bronze Oxide coating is usually used in conjunction with Cobalt Steel coating. The additional coating minimizes the stress applied on the surface material while also further increasing the tempering power of the drill bit.
Bronze Oxide coating is often applied to drill bits used for cobalt steel applications.
Titanium Nitride coating is an expensive coating used for drill bits that make them last longer, more resistant to heat, and harder at the same time.
This type of coating is applied to drill bits even when drilling through materials that aren’t typically known for being extremely hard.
This includes Aluminum and Magnesium, as well as Iron and Steel. However, what makes Tin coating stand out is that it provides much better benefits than both Black and Bronze Oxide can provide.
Meant for precise drilling applications, Zirconium Nitride coating reduces friction and improves the drilling strength of brittle drills while also making them more resistant to heat.
Zirconium Nitride coatings are usually applied to brittle and sensitive drill bits to minimize the risk of damage resulting from improper handling.
What Are Other Factors to Consider When Choosing the Right Drill Bit?
Here are some other factors to consider when choosing a drill bit.
The shape, edge, or angle of the drill bit point
In addition to the material used for the drill bit and coating, the angle or edge of the drill bit point can also affect how effectively it can penetrate materials.
Flatter points are typically used for harder materials, while steeper points are best for softer materials. However, for precise applications, you’ll want to use drill bits with split points.
This is because the design prevents the bit from moving into another drilling point area even if you don’t apply much force to hold it down.
The size of the drill bit
The size of the drill bit should also match the thickness of the structure of a particular project. Not to mention, the size will also determine how big of a hole you’re going to bore through the material, so be careful.
When buying sets or packs of drill bit, you’ll typically find them bundled in sizes of 1/16” up to 1/4″.
These are the most common sizes used in home projects. However, there are other sizes that you may want to consider as well.
Larger drill bits, like 1/2″may come in handy, as well as other drill bit sizes like 7/16”, 5/16” and 3/8”.
Chuck size and type
Once you’ve chosen the right size of the drill bit, as well as the material and coating, you then have to make sure that you can secure the drill bit properly through a chunk that helps tighten the shank or shaft of the drill bit for added security when you’re using the drill.
The typical household drill comes with an 3/8” chuck, while heavy-duty drills usually use anything between 1/2″ and 5/8” chucks.
It’s also important to keep in mind that larger drill bits may come with smaller and even bigger shafts and shanks. This is to help them accommodate other chuck sizes.
Here are the different types of shanks and/or shafts to consider in conjunction with chuck size:
Round shanks and shafts
This type of shank/shaft is usually used to center a drill bit in the chunk. This is the most common and is typically found in most houses’ drills.
Hex shanks and shafts
This type of shank/shaft helps provide more torque and grip. These are usually used in cordless drills that require more grip and torque to compensate for their lack of power, especially in wireless mode, compared to wired drills.
This type of quick-change mechanism is also ideal for professionals since it makes it easy to replace and remove a shft without needing to tighten and loosen the chuck.
Slotted Drive System (SDS) shanks and shafts
This type of shank/shaft is usually used on hammer drills. This holds the bit steady while the hammer drill moves back and forth to bore a hole.
There are flat areas and slots found on this type of shank/shaft that helps make it easier for the chuck to hold the drill bit when it is used on a hammer drill.
Are you using a standard drill or an impact driver?
Another thing to consider is whether your drill is actually an impact driver or whether it’s just a regular drill.
Standard drills are capable of using both regular drill bits and also drill bits designed specifically for impact drivers.
However, impact drivers can only use drill bits designed for it. If you use regular bits, they may shatter, as the impact driver works a little differently. An impact driver has a mechanism that pounds the bit to drive the fastener even faster.
Hence, identify first which type of drill you’re using.
How to Take Care of Your Drill Bits
Regardless of how brittle and durable your durable bits are, how you drill holes and handle your drill bits play a big role in how they retain their effectiveness.
Here are some tips to help you take better care of your drill bits.
- Drill as slowly as possible.
- Don’t drill the hole in one go. Take the time to back out of the bored hole every now and then. Some material can get lodged in the hole and you’ll want to remove it every now and then for a cleaner hole. Also, periodic breaks help relieve some of the heat from the drill and drill bit, minimizing any and all changes of breaking and overheating.
- Use light machine oil to lubricate both the material and drill bit to minimize stress and heat. You can use kerosene or soapy water to lubricate softer metals like brass or aluminum. Alternatively, you can use water to lubricate diamond drill bits when handling more delicate materials.
- Secure the material with a vice or a clamp. Don’t hold it. This is dangerous and unnecessary. Don’t even risk it.
- Use the right kind of bit for the material. Otherwise, you’ll end up damaging the material or your drill bit, or even your drill.
It’s a common misconception among most DIYers that it is okay to use a single type of drill bit on a variety of surface materials. This is not only wrong, but it is also dangerous.
Using the wrong kind of drill bit puts the user at significant risk of the drill bit slipping away from the hole point, or injury and/or damage from chipped or broken materials. The wrong drill bit also makes the drill more prone to overheating.
Both of these things can only add to your costs if and when they happen.
The wrong kind of drill bit also adds additional and unnecessary work. It will effectively waste both your time and money by making you work more on your project when you could’ve finished it by exerting less effort.
You’ll know that you’re using the right kind of drill bit for a particular project when you don’t have to apply much pressure to bore a nice and clean hole.
For both safety and efficiency reasons, it’s incredibly important to choose the right drill bit.
Hopefully, after having gone through our article, you now know how to choose the right kind of drill bit for a particular material.