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Core Drilling Best Practices

Before you begin drilling, it's important to have the right equipment, tools, and techniques to maximize drilling accuracy and efficiency. Following these core drilling best practices is crucial for achieving precise and efficient coring.
  • Secure the core drill rig with either a mechanical anchor, vac system, or using a jack screw.
  • Never stand on the base of the drill without anchoring the drill.
  • Level the drill by using the base's leveling screws and a small level attached to the column permanently or by a magnetic strip on the level. This ensures a perpendicular hole.
  • Never let the bit spin in the hole without applying pressure. This causes the diamonds to round off and the segments will overheat and glaze over.
  • Turn on the water before starting the drill motor. Otherwise, the water jacket seals heat up and become brittle, losing water.
  • When the bit encounters steel (rebar), relax pressure about 1/3 and allow the bit to cut at its own rate DO NOT PUSH THE BIT

DOWNLOAD CORE DRILLING BEST PRACTICES

Stand Selection

 

To get the most productivity during your next core drilling project you need a tool that matches your workload and the application that you're working on. Husqvarna brings you a range of core drilling stands made to fit their highly productive core drilling machines. Check out our blog on how to select the right core drill stand for your next core drilling job.

 

Mounting and Anchoring

Mounting and anchoring a core drill before use is essential for safety, precision, and efficiency. It ensures stability, reduces the risk of accidents, and enables accurate and controlled drilling operations. Core drills are powerful tools that generate significant force while in operation. If not properly mounted and anchored, the drill may experience excessive movement and vibration, leading to a loss of control. This can pose a safety risk to the operator and others nearby. Mounting & anchoring the core drill securely ensures stability, minimizing the chances of accidents or injuries. Check out our in-depth guide to core drill anchoring.

 

 

A mounted and anchored core drill provides a stable base, allowing for controlled and precise drilling. It helps maintain the intended drilling angle and direction, preventing unwanted deviations or errors. This is particularly important when working on critical projects that require exact measurements or when creating openings for pipes, wires, or structural elements. Mounting and anchoring a core drill not only improves safety and precision but also improves core drilling efficiency. The stability provided by a secure mount allows the drill to have consistent pressure and maintain a steady drilling speed. This leads to smoother drilling operations and less operator fatigue. It also minimizes the chances of drill bit damage or premature wear, ensuring optimal performance and longevity of the core drill and diamond drill bit.

Anchoring into Asphalt

The process of anchoring a core drill in asphalt can differ from anchoring into concrete. When anchoring into asphalt ensure your surface is clean and free of obstructions. In asphalt, the most common anchoring technique is using an anchor bolt or spike specifically designed for asphalt surfaces. These bolts create a secure connection between the stand and the asphalt. Asphalt tends to be a softer, more flexible material. Proper anchoring techniques can mitigate the instability of the material and provide a strong base for your core drill motor.

"Opening" Your Diamond Core Bit

When drilling high PSI concrete or concrete with very hard aggregate (river rock, flint rock) the bit will sometimes "glaze over" or becomes dull. To open or redress the diamond bit, do the following:

  • Set water to 1/2 for a few minutes and as the bit starts to increase speed, gradually increase the water until the flow is back to the original state.
  • Pour masonry sand into the slurry then follow the above directions
  • Add a sandblasting media to the slurry and follow the above directions.
  • Drill the bit into a cement block, soft vitrified grinding wheel, or cinder block. Repeat the procedure until the bit is open again. 
  • When finished drilling, turn the water down very low and back the core bit out of the hole with the motor running.


 

Common Core Bit Symptoms:

Symptoms

Cause

Potential Remedy

Loss of Segment The bit is too hard for the material you are drilling

Overheating due to insufficient water for cooling and flushing

The machine setup is not rigid loose material is in the cut & the bit segment hangs

Use a softer bond if possible. Increase motor RPM if possible

Increase the water flow to where the slurry is a chocolate milk consistency.

Tighten the anchor, and check the vacuum system for proper vacuum pressure.

Segment Cracking The bit is too hard for the material being drilled.

The machine setup is not rigid.

Use a softer bit if possible. Increase motor RPM.

Tighten the anchor, and check the vacuum system.

Barell Cracking Too much feed pressure.

The segment is too hard for the material being drilled.

Back off the pressure.

Use a bit with softer segments.

How to Adjust RPM for Water Control

For the best core drilling results, proper water control is key. The slurry should have a chocolate milk consistency to it. Too much water will wash away the abrasive slurry which is key to keeping the diamond exposed in the bit - too little water will cause the bit to overheat/glaze over.

How to Maneuver Coring into Rebar

If you find yourself drilling and run into rebar, you have a few options. Drilling into the rebar with a diamond-tipped core bit (like our Muscle Bits) is a good option as the diamond segments can cut through the rebar encased in concrete. We recommend slowing the RPMs of your drill in the rebar and turning up your water flow to continually flush out the metal debris created from the rebar. Once you are through the rebar, adjust the water and RPMs to normal operating conditions.