How to Use a Core Drill: A Step-By-Step Guide

Video how to core drill

If you’ve ever needed to cut a large diameter hole through a solid brick or block wall, then a core drill is the tool for the job. Whether you’re running cables, waste pipes, or installing extraction fans, using a core drill will make your task much easier. But how do you choose the right type of core drill and use it effectively? In this guide, we’ll walk you through everything you need to know about using a core drill.

How to Use a Core Drill: A Step-By-Step Guide

What is a Core Drill?

A core drill is a specialized drill bit that cuts large holes through masonry and concrete, removing the center part of the hole (core) as it drills. There are many different core drill sizes, each representing the size of a commonly used pipe, cable, or duct. This ensures that once the hole is drilled, the intended object can pass through with ease.

Carbide Core Drill Bits

Carbide core drills are the most affordable option when it comes to core drilling. These drill bits feature carbide “teeth” that surround the circumference of the bit. As the bit rotates, these teeth bite into the surface and cut their way through, creating the desired hole. While it is not recommended, some people use hammer action with carbide core drill bits to increase cutting speed. However, this can wear out the bit faster and may result in larger holes than intended.

Diamond Core Drill Bits

Diamond core drill bits are a step up from carbide core bits. The teeth on a diamond core bit contain embedded diamonds, which are extremely hard and grind their way through the surface, creating a clean cut. There are two types of diamond core bits: wet cut and dry cut. Wet cut diamond core bits use water to cool them while drilling, while dry cut diamond core bits are used without water. It’s important to keep diamond core bits as cool as possible to prevent damage to the cutting teeth. Dry cutting diamond core bits are generally used indoors, while wet cutting bits are used externally.

What Type of Power Drill do you Need for Core Drilling?

A core drill should always be used with a power drill that has a minimum power output of around 800 watts and a maximum of around 1300 watts. Your drill should also have a variable speed function (between 100 and 300 rpm) and a safety clutch. The safety clutch is important because if the core bit gets stuck, the drill can rotate instead and potentially cause injuries.

How Fast Should you Drill When Using Core Bits?

The drilling speed will depend on the size of the hole and the density of the material. As a general rule of thumb, smaller holes up to 30mm in diameter can be drilled at higher speeds (up to 3000 rpm), while larger holes around 400mm should be drilled at slower speeds (as low as 300 rpm). Always refer to the manufacturer’s instructions for the recommended drilling speed for your specific drill and core bit.

Preparing for Drilling Holes Using a Core Drill

Before you start drilling, always check for hidden cables or pipes in the wall. Use a cable and pipe detector to scan the surface of the wall. If any cables or pipes are detected, lights or a buzzer will indicate their presence.

How to Drill a Hole using a Core Drill

Now let’s walk through the step-by-step process of drilling a hole using a core drill.

1. Mark the Exact Drilling Spot

Measure and mark the exact spot where you want to drill your hole. Ensure there are no mistakes, as drilling a large hole in the wrong place can be difficult to fix.

2. Screw the Core Bit onto the Arbor

Attach the core bit to the arbor by screwing it in tightly.

3. Insert the Guide Drill

Insert the guide drill into the arbor until it becomes tight. The guide drill is used to keep the core bit in position while cutting into the wall.

4. Insert the Core Drill into Your Drill Chuck

Insert the core drill assembly into your drill chuck, making sure it is held firmly in place.

5. Set the Correct Speed and Turn Off Hammer Action

Set the correct drilling speed for your specific drill and material. Additionally, turn off the hammer action if your drill has this feature.

6. Start Drilling

Position the guide drill on the marked spot and start the drill slowly, increasing the speed until the guide drill bites into the wall. Hold the drill level and continue drilling until the core bit teeth hit the surface. Take breaks to let the bit cool down and ensure it is still rotating.

7. Finish from the Opposite Side

For the neatest cut and finish, move to the opposite side of the wall and position the guide drill back into the hole it previously made. Drill from this side until you have a nice, clean hole.

Remember to always prioritize safety by wearing appropriate safety equipment, such as gloves, dust masks, and eye protection.


Q: Can I use a core drill with a cordless drill?
A: While a corded drill is generally recommended for more consistent power output, high-quality cordless drills (minimum 24v) can provide enough power for core drilling tasks.

Q: How long does a core drill bit last?
A: The lifespan of a core drill bit depends on various factors, such as the quality of the bit, the material being drilled, and how it is used. Diamond-tipped bits generally last longer than carbide bits.

Q: Can I use a core drill without water?
A: While wet cutting is recommended for diamond core bits to keep them cool, some dry cutting diamond core bits can be used with or without water.


Using a core drill can make drilling large holes through masonry and concrete much easier. By choosing the right type of core drill and following the proper techniques, you can achieve clean and precise results. Remember to prioritize safety and take your time when using a core drill. For more information and recommendations on the best drill press for metal, visit Best Drill Press For Metal. Happy drilling!

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