Core Drill Bits Selection Guide

There are a lot of options for drilling a hole. Do you want to hang a painting on the wall? Drills can do that for you. However, you need to use a core drill bit for anything larger than a regular small diameter.

A core drill bit is a crucial component of a core drill. This is the determining factor on core drilling’s core stability and core recovery.

There are many reasons behind having a good core drill. Many people use core drills for their construction projects and other similar purposes.

Core Drill Bits

Regardless of what you need these core drill bits for, a few factors will help you choose what type of core drill bits you need for the job.

For example, you might find yourself choosing between Carbide Core Drill Bits and Diamond Core drill bits or wet vs. dry drilling, and it’s essential to know which is the correct drill bit for you.

Not only that, but it is also vital that you consult with someone before actually buying these core drill bits. First, you have to make sure that it’s compatible with your drill, and second, ask for recommendations from friends or your local hardware store on what core bits you need.

This article will help you learn all the things you need to know about core drill bits. This is great for people that have little-to-no knowledge about core drills and want to use specific core drill bits for their construction needs.

What is a Core Drill Bit

Core drill bits are essential to construction projects, demolitions, core retrieval, and core examination. It’s an important tool that can drill through surfaces and recover the drilled portion.

For starters, core drill bits are positioned at the edge of your core drills. They’re the one that makes contact with the surface and pierces through whatever material they need to punch through.

Here’s a fact for you, ancient Egyptians started core drilling, whether they need some precious core to be preserved or use these drills to mine materials. Core drilling is still an excellent method of extracting these cores that can be used for improving technology, preserving cores, or, more realistically, in the modern world, to help engineers in their construction projects.

The materials of these core drill bits, size, and usability are essential when choosing a core drill bit. Knowledgeable operators are also needed to operate these machines.

Importance of Core Drill Bits

Core Drill Bits

There are many vital factors to look out for when using core drill bits. However, before purchasing one, we should know the importance of core drill bits.

Core drill bits have made it easier for engineers, workers, and researchers. They play a significant role in the core drilling industry.

Here are some of the reasons why core drill bits are essential:

  • Pierce through Concrete

In the construction world, piercing through concrete may be one of the most common uses of these core drill bits.

Together with the core drills, the core drill bit is the component that removes a cylinder of concrete for different construction purposes.

These ‘construction purposes’ can include plumbing, electrical wiring, drainages, and maintenance holes. These bits simply drill through the concrete, making precise holes.

  • Make Clean Cuts

Depending on the brand, quality, and material your bit is made of, you can make clean cuts with these excellent tools.

The core drill bit’s responsibility is to deliver clean, accurate, and precise cylindrical cuts on most surfaces, wet or dry. It’s all possible with the help of core bits.

  • Better Core Retrieval

Are you preserving a core for research purposes? Don’t worry. Core drill bits make that possible for you. Bits are designed to be cylindrical to make sure your core is recovered in excellent condition while creating a hole on the surface.

  • Custom Core Sizes

Since core drill bits come in different sizes, you also have many choices for extracting custom core sizes.

The size of your core bit determines the core size. Having custom core sizes is beneficial for making small holes for wiring purposes or large holes for utility usage.

  • Core Hole Stability

Stability is essential after the drilling process. You don’t want your wall, ground, or whatever it is you’re drilling to crumble down after you’ve done your work.

Poor quality core bits can damage the surrounding areas of your coring spot.

Core stability depends on what core bit you are using. For example, using a diamond core drill bit increases the core hole stability significantly.

Different Types of Core Drill Bits

There are different types of core drill bits in the market. Each type has its pros and cons that separate them from the other core drill bits.

Many features separate one type of core drill bit from the other. For example, diamond core bits may be a better choice when retrieving cores in paleo oceanic formations.

Before getting to know the different types of core drill bits, we should first talk about the operation, the core sample, and the method to get these core samples.

That way, you will know what type of core drill bits to use and your drilling project’s difficulty level.

The Operations

The core drills will be used by skilled operators who know how to use the core drills efficiently and adequately.

Three primary coring operations complete the core drilling process: the actual drilling to the ground, retrieving the core sample from the drill bit, and lubricating the inner tube assembly to resume drilling.

The lubrication process will allow fluids to pass through the drill string and cool down the barrel. However, if the core bit wears out, it will no longer do an excellent job at coring and needs to be replaced.

Core Sample

Obtaining the core is the ultimate objective of the core drilling process. The location is essential when choosing the core bit because it determines the integrity of the core that you’re obtaining, the density and hardness of the material, and the amount of lubrication you need.

The core sample is related to the surface you’re coring on. That’s why it can help you choose what type of core bit you need for the job.

Some core bits may even retrieve the core sample in better condition than the other. However, if the purpose of coring is just to make holes, then either one will do a great job.

The Method

There are two widely known ways to do core drilling: the conventional way and the wireline. The main difference between these ways is the way they recover the cores.

The conventional way requires you to pull out the entire drill string for every drilling cycle. However, in wireline core drilling, the overshot and the inner tube are brought up to the surface using a wireline hoist, allowing the bit to stay in the hole.

The things mentioned above are some of the basic knowledge you should know about core bits. Now, we’re going to give you a few examples of core bits.

There are two types of core bits widely used in the coring and are available for purchase in the market right now.

Here are the things you need to know about diamond core bits and carbide core bits:

1. Things You Should Know About Diamond Core Bits

Diamond Core Bits

If it isn’t obvious in the name, diamond core bits are drill bits welded with tiny particles of diamond, the most rigid material known that can be used in coring and drilling.

Since these diamond core bits are made with rigid materials, it’s easier for the drill to cut through various materials.

Additionally, the diamond core bits may cost a bit more expensive than the other core bits, but trust us, it’s definitely worth the money.

Besides, diamond-engrained tools have an excellent reputation in the market for doing their job with the utmost quality. Because of the smoothing effect of diamond tools, diamond core bits enable the operator to make smooth and precise cuts.

It also stays cool in areas with high temperatures, which means the bits won’t easily be broken or damage the workpiece.

2. Things You Should Know About Carbide Core Bits

Carbide Core Bits

Carbide core drill bits are made out of rugged metal. They’re either made out of solid tungsten carbide or have tips covered in a tungsten carbide cement.

Skilled operators can use these carbide core bits because of their long life and excellent durability. Wear and tear can’t be avoided entirely in core bits; however, you can sharpen carbide core bits to extend their lifespan.

According to Emy Guttenkunst, a higher rotational speed leads to an increase in temperature. This means without enough lubrication, and the bit will wear out faster.

Core Drill Bit Sizes

You must know the size of the core drill bit that you want to use for your construction and coring needs.

People have different needs regarding choosing the right side of the core drill bit in diameter.

For example, if you need to make a small hole through a wall to make sure some cables can pass through walls without being too large for people to see, you need a core bit around 30mm in diameter.

Here’s an example from Unika Core Drills that shows a complete chart of their diamond core drill bits, together with the sizes they have.

The illustration above is just an example of the diamond core drill bits and their sizes. The DC (set) has an average diameter of 66mm, which might be the commonly used size today.

However, if you’re planning on purchasing a core drill bit today, make sure the core bit you are buying is also compatible with the drills of your manufacturers.

It’s best to give your manufacturers a call first or ask your local hardware store if you can test out the core bit first. If it fits, you buy it. If not, you have to spend more time looking for another bit that’s compatible with your drill.

Overall, this graph is the best example of the wide variety of sizes you can purchase the core drill bits.

Concrete Coring:  Carbide Core Bit vs.  Diamond Core Bit 

Carbide Core Bit vs. Diamond Core Bit

Concrete coring has been one of the main reasons why people purchase these core drill bits in the first place.

Core drills are essential to your work, whether they want to drill through the walls to make passageways for electric cables, sockets, and even tubes for pipelines.

Where do core drill bits come in? Core drill bits are essentially the tip of the spear of every core drill bit. The direction of the spear works better if it’s sharp and tough. Like how core drill bits work, it’s better to have a sharper and tougher core bit for drilling.

Here are the general pros of both Carbide Core bit and Diamond Core bit:

  • Have Custom Drill Bit Sizes
  • Drill through Various Types of Materials
  • Are Great for Concrete Drilling

When it comes to core drill bits, Carbide and Diamond core bits are the biggest rivals in the industry. That’s why we have set up a little table to understand the pros and cons each core bit has to offer. Let this be a guide for you on what core bit to choose.

Here are the pros and cons of Carbide Core Bits vs. Diamond Core Bits to help you decide which core bit to use in the future.

Carbide Core BitDiamond Core Bit
PROS
  • Carbide core bits are an excellent choice for concrete coring and compared to diamond core bits.
  • The bit is covered with tungsten (a rigid metal) to make sure to pierce through concrete easily.
  • The carbide core bit enables you to sharpen the core bit to enhance performance.
  • The outer barrel is lined up with tiny diamonds to make sure it produces sharp cuts.
  • Diamonds are rigid materials, which means compared to carbide core bits, they will have more excellent durability without sacrificing too much of their high-quality performance.
  • The diamond’s smoothing effect enables the core drill to achieve accurate holes.
  • Because of the high cutting power, it has better hole stability and core recovery.
CONS
  • Compared to diamond core bits, it’s not as long-lasting as you think.
  • You may sharpen the core bit. However, this will make the bit thinner, shortening its life span as you point the bit.
  • Typical carbide core bits pound the surface it is drilling on. Its hole stability is not the greatest.
  • Compared to carbide core bits, these are significantly more expensive than carbide core drill bits.

Although not mentioned in the table above, a skilled operator must use core drills to avoid accidents and unwanted hazards.

A skilled operator should handle the job because, one, they can get the job done faster, two, they help you avoid accidents that may happen, and three, overall they do a pretty good job at their field of work, that’s why you should let them handle the job.

INTRODUCING a Clean New Way to Core Drill Concrete Surfaces (Dry Drilling) 

Core drilling can be very dusty, dirty, and unnecessarily messy. In the past, core drilling is a very sloppy job, to begin with. From drilling to the surface and recovering the core, dust can gather around you, making you and the workspace around you dirty.

With today’s technology, it’s entirely possible to do core drilling while being clean simultaneously.

Here’s a video of Cardi showing us the Core Drilling with Micro-Percussion Technology. They use. That’s pulse technology to make sure that they have a cleaner cut with concrete. That way, they can drill faster and more hygienic.

Overall, this “Pulse Technology” can help you have a cleaner way of drilling because this technology makes the drilling clean and fast at the same time.

Wet vs. Dry –  Concrete Core Drilling

According to the drilling method, wet core drilling is better because it can remove dust particles, slightly increase drilling speed, and keep the site/area clean.

However, there are some upsides to dry core drilling as well. Here’s a table explaining what wet core drilling and dry core drilling are.

Wet Core DrillingDry Core Drilling
Wet core drilling is mainly sought out by most of the drilling techniques in the industry.

  • It reduces dust particles in the air.
  • There are many applications of wet core drilling (includes plumbing, masonry, etc.)
Dry core drilling is just drilling by the name itself, no liquid involved and just drilling.

  • A higher amount of pressure is placed on the drill bit, reducing the drill speed.
  • Excellent for drilling holes for electrical purposes (landline, electrical cables, etc.)

Here’s a video showing a New Clean Way to Core Drilling by Hilti.

Overall, you should choose wet core drilling when drilling concrete because of its cleaner way of drilling. Dry drilling will do the job if you cannot involve liquid when preparing (drilling for electrical purposes).

Frequently Asked Questions

Can I perform wet and dry drilling with diamond core drill bits?

Depending on the brand, you can perform both wet and dry core drilling with diamond core bits.

The versatility of these core bits is so impressive that all you need to do to switching from wet to dry drilling is clean the core barrel inside out, and you’re good to go.

Which is more durable, Carbide Core Drill Bits? Or Diamond Core Drill Bits?

Durability always comes down to how the user uses the core bits. With ample lubrication and maintenance, both core drill bits can last for about 1-2 years of constant usage.

However, material-wise, it’s a clear winner that diamond core drill bits are better because diamonds are tougher than tungsten (the rigid metal found in carbide core bits). Which means it can guarantee you a long life span.

Is it better to rent core drills near me?

Yes. First, it’s cost-efficient, second. Yourigid metal can also request an operator from the rental service to assist you with using the core drills.

Should I hire core drill operators?

Although learning how to use a core drill is hard for some people, hiring other people to do the job for you is a great alternative.

Just give them instructions on what to do, and you should expect a great job in a short amount of time, considering you hire skilled core drill operators.

How often should I change my core drill bits?

There’s no specific time from on how often you should change your core bits. However, just by examining the bit itself, you can determine whether you should change bits or not.

If you feel and see that the teeth of the core drill bits are wearing off, then it’s a great sign that you should change them sooner or later.

Not only that, but if you also feel that it’s taking longer to core through concrete than usual, it can also be a great sign that your core drill bit needs changing.