A concrete core drill is a large, high-torque drill motor with a large threaded arbor for attaching a concrete core drill bit. These drill bits resemble a hollow tube with a threaded nut on the top and a series of rectangular "teeth" set in the bottom of the bit. Applying pressure on the core drill forces the tip of the core drill bit against a concrete surface. The teeth grind material around the perimeter of the drill bit, leaving a solid core of concrete matching the opening of the hollow core drill bit.
Dust fills the drilling area when the teeth of a core drill bit contacts the surface of concrete. Along with dust, friction heat is generated between the teeth and the concrete. A pressurized water tank connects to the concrete core drill to reduce heat and convert the dust to dirt slurry, which remains on the surface of the concrete rather than flying into the air. Although a constant supply of water increases safety and extends the drill bit life, another safety issue arises when using a concrete core drill.
Large-diameter drill bits create a lot of force on the base of a concrete core drill. This can damage the drill or property or cause serious injury to the drill operator. Securing the base to the concrete keeps the core drill safely in position during the drilling operation. Standard concrete anchors sized to fit the slotted mounting holes and placed in the concrete correctly can secure the base of the drill to the structure. After a concrete core drill is sitting securely in place, one additional safety issue still exists.
Drilling on a concrete structure with an open area below creates the danger of a concrete core dropping from the center of a concrete core drill bit and hitting a person walking or working below the drilled hole. Proper danger markings are required to alert people working below the concrete core drill of the dangers lurking overhead. Running red "danger" tape surrounding the area under the core drill will keep people safe. While hanging the danger tape, the concrete core drill operator can survey the area to ensure that no other hazards remain in the area under the drilling operation. Taking the proper precautions will ensure the safety of the concrete core drill and its operator.