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Concrete is a hard, dense substance made from aggregate material. It’s durability and damage resistance makes it a popular construction material. Many DIYers avoid drilling into concrete out of fear or lack of knowledge.
A handheld drill or hammer drill, when fitted with a masonry bit, can drill directly into concrete.
How to Drill Into Concrete
Here are the steps for using a drill on your concrete.
- Measure and mark the concrete to be drilled. Using a hammer, lightly tap a nail or awl against the surface of the concrete to create a tiny dent. This dent is where you will place the drill bit when you’re ready to start drilling.
- Attach an appropriate drill bit. Masonry bits are made from a hardened metal such as tungsten carbide and are designed to cut smoothly through concrete. They have a paddle-shaped end that is useful for removing waste material. Insert the bit into the jaws of the chuck and tighten it securely. Make sure you are using an appropriately sized bit for your drill.
- If drilling a pilot hole, the bit should be slightly smaller than the diameter of the screw that will follow it. If you need to bore a large hole, it’s best to start with a bit 3-4x smaller than the diameter of the intended borehole. You can then increase the size of the hole gradually, using larger bits.
- Don goggles to protect your eyes. Drilling concrete releases silica dust. Inhalation of silica dust has been linked to serious respiratory diseases like silicosis. Protect yourself from silica dust with a respirator.
- Determine how deep the hole needs to be. When a screw is driven into concrete, it creates waste in the form of dust. Some of this dust will exit the hole as the screw goes in, and the rest will settle at the bottom, so it’s advisable to drill ¼ of an inch deeper than you truly need.
- Plan ahead by setting a depth guard. If your pilot hole is too shallow, the screw won’t be able to penetrate the concrete. If it’s too deep, you risk creating a crack or weakening the concrete. A depth guard allows you to precisely control how deep the bit goes. Hammer drills usually have adjustable metal rods called depth guards. These prevent the bit from entering too far into the concrete. If you don’t have a depth guard, you can improvise one by wrapping a piece of painter’s tape around the drill bit.
- Adjust the drill clutch. A dial on the barrel is used to adjust torque on a handheld drill. Torque is a rotational force, therefore the torque setting dictates how forcefully the bit will rotate. High torque settings are best for concrete, because it is extraordinarily hard and dense. When you’re ready to drill, connect the tool to power.
- Holding the drill like a gun, place the tip of the bit against your indented mark. Plant your feet and square your shoulders. Use a level to ensure the drill is at a 90 degree angle. Some drills have a bubble level integrated into their design, making this step easier.
- Pull the trigger on the drill to start it up. Your arm and shoulder will absorb some recoil, which may change the angle of the drill, so go slowly and check the level often. Allow the bit to gradually eat it’s way through the concrete. Stop drilling periodically to remove waste material. The paddle-shaped end of the bit helps expel accumulated dust. You can also use a vacuum to clean up as you go.
- Check your bit for damage and replace it if necessary while drilling. You may notice changes in resistance that cause the machine to act unpredictably. Concrete contains large and small pieces of rock that are too hard for a handheld drill to penetrate. Insert a nail into the hole and tap it lightly with a masonry hammer to break up the rock.
- When the hole is the desired depth and diameter, stop. Disconnect the drill from its power source to avoid accidental start up. Use a vacuum hose to clean out the hole.
Concrete Drilling Without Overheating the Bit
Friction generated by the bit rubbing against the concrete will cause the bit to heat up, possibly breaking it. To prevent this, take regular breaks while working, allowing the bit to cool down.
If you have a cordless drill, you can spray water over the drill bit as you drill to keep it cool. A less messy solution is to keep a cup of water near your workspace and periodically dip the tip of the bit.
Water-based cooling methods should not be used with corded drills due to the risk of electrocution. Instead, point the hose of a vacuum at the work area and turn it on. This will pull cool air over the surface of the bit. It has the added benefit of reducing the amount of concrete dust released into the atmosphere.
Is a Drill the Best Tool for Drilling Concrete?
A handheld drill with a masonry bit will take a long time to drill through concrete. Cordless drills have less power than corded models, so drilling through concrete with a cordless drill will take even longer. If you only need to drill a few holes and have a significant supply of patience, a drill will do the job.
If you plan to make many holes or frequently need to drill into concrete, consider purchasing a hammer drill. This powerful tool combines rotational force with vibration to smash and cut its way through concrete. If you’re in the market for a new drill and want to drill through concrete, consider a combination model that can be operated in two modes — drill-only or hammer-and-drill.
A drill or hammer drill can be relied upon to drill through concrete, provided the right steps are taken. Use a masonry bit, working slowly and carefully. Keep the drill bit cool using water or a vacuum to avoid dulling and possible breakage of the drill bit.
The silica dust released during the drilling process is dangerous. You must wear a respirator when drilling concrete.