Working with concrete can be tricky because though we think of the material as very dense and tough, it is actually easy to end up cracking concrete. When nailing, bolting or anchoring in concrete, follow these tips to make sure you don't split the rock and ruin the surface.
The Right Drills
To ensure your job goes smoothly, you first need to make sure you use the right tools. If you do not use the proper drill and drill bits when inserting bolts or nails into rock, you could end up cracking the concrete. Use drill bits that are especially made for concrete and make sure that they are sharp, as dull drill bits will mean that you need to push too hard, which can lead to cracks as well as your drill overheating.
If you are worried about cracking the concrete, another option is to start using a smaller drill bit than you would ultimately like. The smaller bits will work through the concrete easily, and then you can go over the initial hole with a bigger drill bit. Though it adds another step, it will make drilling the holes easier and help to preserve the drill bits. If you don't own the proper drill and bits, you can always rent them instead of buying a whole new drill and bit set. This would make sense especially if what you are working on is a one-time project.
Of course we think of concrete as a very strong material, and though it is robust, there are actually lots of tiny holes in the rock. Because of this, you must be careful not to drill your holes too close to one another. If you do not space your holes properly, you could definitely end up splitting the concrete.
Slow and Steady
Do not be in a rush to drill. If you drill too fast and/or set the drill to too high a speed, you will definitely end up cracking the concrete. Firstly, make sure your drill is set to a very low speed, as this will help keep the concrete intact and will also ensure that your drill bit will not get damaged. When drilling, apply some pressure but do not press down with all of your strength, which will also damage the bit and the rock surface. Once you feel the drill making some progress in the concrete, it is always a good idea to stop, remove the drill and give the hole a once-over to ensure everything is progressing okay and then continue to finish drilling the hole.
When you feel you've gotten as deep into the concrete as you need to go, don't just yank the drill out of the rock, as you will either damage your drill bit or end up cracking the concrete and ruining the hole. Instead of just pulling the drill out of the concrete, put the drill on a very low speed and gently work the drill out of the rock, so that you are reversing it out of the hole instead of just removing it.