Guide written by:
Sebastian, self-taught DIY-er, Exeter
A large, robust tool, the core drill is designed to drill concrete and other materials using a very wide bit sometimes called a bell or a saw. Depending on the nature of the material, you can choose between dry or wet core drilling.
- Dried up
What is a core drill?
Generally made of galvanized steel or other resilient metal, the core drill makes drilling holes clean and easy even when working with difficult materials such as concrete, cement, or stone.
The key to working with these tough materials is the core bits diamond coating which makes it extremely resistant to wear through use.
The core drill provides unparalleled precision and performance.
What is diamond core drilling?
Non-diamond bells are available for use in core drilling, but diamond bells are the key to improving the quality of your work.
The technique of diamond core drilling provides an easier and better quality of work than other techniques for boring holes.
This process allows core drilling up to 1000 mm deep.
What is a coring?
Core drilling is used to:
- Create a passage for pipes, wiring, and other utilities—water pipes, electrical wiring sheaths, waste water removal, etc.
- Acquire core samples—core drills are used to drill into stone, wood, ice, or other materials to produce samples used in scientific research, industrial drilling, or testing bedrock at a construction site among other uses.
- Bore any large holes—the advantage of core drilling is the ease of creating large holes or openings in any sort of project.
Obviously, this list is not exhaustive.
What are the benefits of diamond core drilling?
Diamond core drilling has many advantages:
- Reduced vibration—this is a huge perk, especially with frequent use. It will help to reduce fatigue and risk of injury and makes using this tool much more pleasant.
- Eliminates dust—as opposed to other methods of hole boring, core drilling removes a solid piece rather than pulverizing it which eliminates a great deal of dust. This is even truer of wet core drilling than dry. The addition of water helps to keep any dust out of the air.
- Relatively quiet—thanks to its narrow profile and hard, resilient material, diamond core drilling produces much less noise when boring a hole.
- Large scale—bells for core drilling come in very large dimensions of both diameter and depth.
- High level of precision—compared with other methods, core drilling is extremely precise, producing results that are accurate down to the millimetre.
What are the different types of core drills?
There are three general types of core drills:
- Annular Drills—these core drills specifically used for drilling metal.
- Diamond Core Drills—as mentioned above, these drills are meant to be used drilling concrete, stone, and masonry.
- Drilling Rigs—used in industries such as petroleum or natural gas extraction, drilling rigs are extremely large versions of the same tool. These huge drills are housed in a large metal structure and are able to drill cores that are kilometres long instead of mere millimetres.
Why dry core drills and water core drills?
Where it is possible and practical to use, water will always make core drilling easier. It is highly recommended for outdoor work and for large diameter drilling.
Water helps to reduce friction, further helping to eliminate noise, vibration, and heat and also helps to eliminate dust.
Dry drilling is recommended for interior work where water would be impractical, but make sure you bring a vacuum cleaner.
For outdoor work and large diameter, water is recommended.
What are the criteria for choosing a core drill?
Three criteria are to be considered when selecting a core drill: frequency of use, the location of use and core size/depth.
Frequency of use
For frequent and intensive use or for diameters greater than 182 mm, choose a fixed core drill. The tool that can produce enough power to do this kind of work is less practical in a portable model. For less frequent use, go smaller scale. If you are frequently changing your location, be sure to pick a portable model.
Location of use
Because water is impractical for most indoor work, use a dry core drill and spare yourself having to mop. While you spare yourself cleaning up water, you will have to clean up dust instead so bring a vacuum. Where water is not a concern, opt for a water core drill to help reduce wear and preserve the machine as much as possible.
Size and Depth
A 220 V core drill of 2000 W will do well for coring less than 500 mm, however, it is better to turn to a core drill at 380 V of at least 4000 W for deep core drilling.
How to fix a core drill
Fastening the core drill allows for better drilling accuracy and safer job performance.
Using bolts or some other form of secure fasteners is recommended for perfect and precise drilling. You can mount vertically or horizontally so that the drill is perfectly stable and the drilling is as simple as possible.
Suction cup mounting
If it is not possible to use a secure means to anchor your drill, it is sometimes possible to use a frame equipped with a suction cup and a vacuum pump. As this technique secures the tool to a surface via a vacuum seal, It is really only possible with a smooth, non-porous surface.
Mounting via strut
Using an aluminium strut or another form of a frame to secure the drill allows you to core without worrying about securing it to another surface. Take this strut with you and use it at multiple sites on multiple jobs as well.
Cleaning and keeping it running
It is important to keep in mind that the most important part of using a core drill is cleanliness. Dust and debris can build up quickly in the motor-box and other moving parts. This will not only accelerate wear on these parts but also increases the risk of the engine seizing or of injury.
To prevent the build-up of dust, debris, or the muddy mixture that accumulates during wet core drilling, requires careful cleaning of every surface after each use, as well as a regular dusting of the engine itself.
Also, lubricating the gearbox and adjusting the clutch is crucial for extending the life of your tool and maintaining its usefulness.
It’s been said above already but it should be emphasised that you use water coring as soon as the site and conditions allow it.
Water drilling keeps the tool cooled and washes away dust and debris resulting from drilling, which guarantees a longer service life than dry drilling.
It is advisable to use personal protective equipment when using these machines such as gloves, goggles, and noise-cancelling headphones. Don’t forget the safety shoes!
For DIY enthusiasts interested in knowing how to choose the accessories related to core drills, follow the advice of our editors and discover their Guides:
Guide written by:
Sebastian, self-taught DIY-er, Exeter, 192 guides
Redo a roof with wooden beams? Check.Advise Mister everybody in the DIY shop? Check.Redo the bathroom plumbing? Check.Fit together, build the walls, paint a partition, throw my hammer in a rage thinking that it will fix the problem? Check. The DIY motto ? Learning is better than delegating… well, it's also a question about your wallet! The satisfaction? The beer at the end of the job! What do the best have in common? The influence of Gyro Gearloose, Mac Gyver and Carol Smiley depending on your generation, a good dose of curiosity, a average hand-eye coordination and a taste for risks… and if it doesn't work, try again! Advise you? I'll do my best!