A core drill is simply a drill that is designed to cut holes into concrete and masonry in a way that removes the core of the hole as it works.
We have covered the different types of core drill in detail here. The most common use for a core drill is to cut holes for pipe, cable or duct work. Industrial core drills are also used for concrete strength tests.
First let’s take a look at how to use a core drill for pipe and duct work.
Before you Start Drilling
If you have never used a core drill before you should familiarise yourself with the owner’s manual of the tool you have bought, and ensure all components have been pieced together correctly.
Even if you are veteran driller, you should inspect your gear to make sure nothing is worn, or functioning incorrectly.
For a beginner, testing out the drill on a piece of dummy material is a good idea. However, we do realize that a spare section of wall or concrete to try out your tool can be hard to come by.
And most important of all is the subject of safety. When using a core drill you need to be wearing the appropriate safety equipment. Gloves, dust masks and eye protection should all be part of your equipment list, and be on standby ready for when you begin.
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Area to be drilled
Before you even pick up your drill to begin the job you will need to check that to make sure no one has been there before you.
This means inspecting the wall to ensure no current cabling or pipe have been laid in the areas that you wish to drill.
A visual inspection (are there sockets nearby, can you see areas where the masonry has been disturbed?) is a good start however the safest way to be sure is to use a wire and pipe detector to scan the wall.
Knowing your measurements
In some instances when drilling a hole (toilet waste plumbing work for example) you will only get one crack at it. This means knowing your measurements and rechecking them thoroughly before you begin.
A lot of plumbing piping comes in universal sizes, and your core drill may well have come with drill bits in line with those standards.
Whatever the situation, it is very important that everything measures up correctly before you begin.
How to Use a Core Drill
With the preparation steps above taken care of, it is now time to start using the drill.
We’ve included a very in depth video above, as in many cases these are easier to follow than a written description.
That hasn’t stopped us from giving it a go however. Below you fill find some helpful tips on using a core drill.
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- Core drilling does not involve hammer action drilling. The process should be smooth and steady; hammering the drill will grind the diamond teeth and lead to a poor finish.
- The drill and core bit should be held level as you work. This will prevent the finished hole from sloping at an angle.
- Drilling the core in one go is your best option if possible. This means the tool will remove the core in one piece on exit. (Use auger extensions when dealing with thick walls).
- Let the tool do the work. Do not force the cutter through the wall – doing so can lead to sections of masonry falling away on the rear side of the hole.
- To avoid any messiness on exit, it is recommended that you drill through and just before penetrating the rear side of the wall, you finish the hole by drill from the other side. This way will guarantee, a clean and professional finish.
Core drilling for concrete testing
Concrete core testing is a very important of construction work that helps to maintain safety standards, as well as the overall strength of a construction project.
By testing the concrete at this stage, engineers are able to solve any potential problems before the build is completed.
Because of this there are strict guidelines on the way concrete testing is conducted.
Covering all of those in detail is beyond the scope of this article.
The best place to read about these is to head to the websites of the various regulatory boards and trade organisations that oversee this.
- ASTM International: Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
- ASCC – American Society of Concrete Contractors
- NRMCA – Ready Mix Concrete Association