When you begin a concrete coring task, you will need to select the right drill. While there are a lot of options available to you, once you understand the right situations under which each should be used, it will be easier to choose one:
Wet vs. Dry
One decision you must make is whether you will use a wet or dry concrete core drill bit. Dry drilling is most often performed when you do not have enough water available. Also, it is not a good idea to use dry drilling bits if the materials you are drilling through are very hard. Dry core bits produce dust, so you will need a vacuum system to remove the dust.
If you need a vacuum, one option is to get a stand attachment. However, this attachment will require that the surface is level or it will need anchors. First, the stand attachment will need to be adjusted so it is level. Then, it needs to be held in place by anchors.
If you can use a wet drill bit, this is a better decision because moisture is good for the drill bit. Moisture will cause the drill bit to last longer. Also, the drill bit will be better able to drill through materials like reinforced concrete.
Handheld vs. Attached
The type of drill you will need is also based on the diameter of the hole you will drill. If you will be drilling a hole that is three inches in diameter or less, you can use a hand held drill. If the hole will need to be greater than three inches, you may need a rig-mounted drill or a drill stand. While you could potentially use a handheld drill, this will usually be a lot of work. However, with smaller holes, it is less work to use the handheld drill because you will not need to take time to fasten it to anything. You will also have less to carry.
Electric vs. Hydraulic vs. Pneumatic
The most common types of core drills are powered by electricity, which means you will need access to a power line. There are also pneumatic and hydraulic-powered core drills. Pneumatic drills will usually require that you have access to an air compressor.
The electric drills are usually 110-120v power. Even if you have access to the necessary power source, ask yourself if the electric drill will be the most convenient or if you would be better off with a tool that doesn't require a power source.
If you still aren't sure which drill to use, consider renting rather than purchasing one. Then, if you aren't happy with your choice, you can more easily get a different one.