Diamond Drill Core Bits

Only start drilling after water starts to flow from the drill bit.

Select the drill speed (R.P.M.) based on the diameter of the core bit. The smaller the diameter then the greater the speed allowable.

If drilling by hand, start drilling at a slight angle, then when a crescent shaped notch has formed, raise the drill to the vertical position.

Do not force the bit - allow the drill to do the work.  Forcing or twisting the barrel can cause binding, overheating, distortion and segment damage.

If hand drilling, keep the same drilling angle at all times to avoid uneven wear to the core bit or jamming.

When removing the bit, turn the water down and back the bit out while the drill motor is still running.

Check the bit periodically for heat marks, cracks in the steel core or segments, or excessive wear underneath the segment.

If excessive vibration or 'snatching' at the core barrel is detected – remove the core drill, remove the core and investigate. Remove any loose  material, pieces of steel rod etc. When drilling brick walls,  wall ties maybe encountered -  remove them with pliers. Failure to fix these problems may result in segment damage or loss.

When the slurry changes colour (usually to gray) or the drill motor speed drops, you are most probably cutting steel. Drop the motor speed down (slowest speed works well) and relax pressure by about 1/3. Raise and lower the drill motor multiple times until you have cored through the steel so the barrel will not bind on the steel. Some operators reduce water after exiting the steel to redress the bit again, but don't forget to turn the water up again afterwards.

Maintain a straight drilling direction. If you allow the barrel to skew , usually the wall of the barrel will bind in the hole or break off segments.

If the rate of drilling has slowed, the barrel may have glazed up. Redress the bit by reducing the water by half for a few minutes, or by drilling into an abrasive material like limestone, a cinder block or similar.

To remove the barrel from the hole, turn the water to very low and remove barrel while drill is still running.

Never leave a running machine unattended.