Holes are drilled into concrete blocks for various reasons that can include the need to pass plumbing or wiring through them, to install vents and to drill anchor holes to be able to attach an object to the blocks. Drilling a hole in a concrete block can be accomplished with different tools, and the tool you use to drill a hole will be based on how big the hole needs to be. A common household drill is not suitable for this job.
Mark the exact location on the concrete block that you want to drill into. Check around the area where you will be drilling for electrical lines, cables, water lines and gas lines. Call the utility companies to come out and mark the locations for you if you are unsure as to what you are drilling into. This service is free of charge and will give you peace of mind in knowing that it is safe to drill into the desired location.
Place the appropriate size masonry drill bit into the hammer drill, and turn the lever or dial on the drill to the hammering and drilling setting. The hammering feature pulls the drill bit back and forth while drilling at the same time. To drill a hole larger than 1 inch, use a diamond core drill. A diamond core drill operates the same as a hammer drill, but it has more power to cut larger holes.
Put on safety glasses for protection. Bits of concrete will fly back at you as you drill.
Place the tip of the drill on the marked location for drilling. Hold the drill steady and squeeze the power button part way in. Allow the tip of the drill to begin routing out a hole. When the beginning of a hole is formed, operate the drill at full speed. The routed hole will help to keep the drill bit from skipping.
Keep the drill level at all times while drilling the hole. You can apply light to medium pressure while drilling, but do not apply body weight to the drill. This will slow the ability of the drill to work and wear the drill bit out. Take a break if necessary; drilling holes through concrete can be a slow process.
Drills for concrete can be rented at tool rental and supply stores.