Diamond Core Drills, commonly used for drilling concrete, can be dangerous if not used correctly. From my years of experience, I have put together a list of tips to make sure you stay safe while operating a Diamond Core Drill.
1. Site Safety
Always make sure that the general contractor has marked the holes to be drilled to avoid liability for hiring any conduits, stress cables or utilities embedded in the concrete. Ensure there is nothing underneath the floor that the core could fall on, once you have drilled through the material.
2. Personal Safety
Ensure that you wear the proper personal protective equipment and refrain from wearing loose clothing that could tangle in the drill motor.
3. Equipment Safety
Make sure that the core drill motor is not loose on the drill stand. A loose core drill motor carriage will cause the bit not to drill perpendicular and will cause it to jam in the hole. Make sure the equipment is properly grounded.
Secure the core drill to the work surface so that there is no movement in the drill stand.
Make sure that the drill rig is level. The set screws on each corner of the drill base will allow you to level the drill out to secure the bit is perpendicular to the material which causes jamming of the bit.
4. Operating Safety
Once the bit penetrates the drilling surface it will not move and will stay in that groove that is created.
Use light downward pressure on the bit and do not force it. Keep the RPM's steady.
Use a constant water flow to clear the cuttings and to keep the bit cool.
When rebar is encountered, the water will turn clear and the bit will slow down.
When the rebar is penetrated, the bit will resume speed and the water will return to a milky color.
If there is diamond segment height left and the bit stops cutting it may need to be re-dressed or replaced. Re-dress the bit to re-expose new diamond crystals by drilling into an abrasive material like a concrete block or a used grinding wheel.
Never strike the barrel with a metal object to free cores, it will dent the barrel. Use a piece of wood instead and adjust the water flow to clear the cuttings that prevent the core from coming out of the barrel.
If the barrel becomes landed, the bit will not drill past the point of the dent in the barrel.