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Core Drilling Guide with Do's and Don'ts

Core Drilling Guide with Do's and Don'ts

Posted by Jason Munslow on 15th Aug 2023

Many skilled tradespeople believe that applying more pressure on the core drill will lead to greater productivity. However, this is not the case. In fact, excessive pressure reduces the milling speed, increases heat build-up, and shortens the lifespan of diamond-tipped equipment.

It's important to clear debris from the diamond tips on a regular basis to improve performance. If dust builds up, it can lead to inefficient milling, overheating, and excessive clutch wear, which may result in segment loss. It's also crucial to service your tools and equipment, particularly core drills, since they are more likely to be affected by debris contamination. Regular servicing can extend the life of your equipment and improve its reliability, which can reduce the need for costly repairs and prevent the loss of fee-earning work if the drill becomes irreparable.

Remember to Wear these four items when core drilling....

  1. Wear Eye Protection
  2. Wear Hearing Protection
  3. Wear A Mask
  4. Wear Hand Protection

Do’s and Don’ts

Dry diamond cores are a popular tool used by many trades for various applications with excellent results. However, certain do's and don'ts should be followed, along with some useful tips to help you achieve the best outcomes.

When using dry diamond cores, it's crucial to prevent dust from accumulating within the hole during drilling. If the dust builds up, it can lead to several problems, with the most serious being the core becoming stuck within the hole. This can cause the machine to "kick," potentially harming the user if the machine doesn't have a safety clutch. To ensure the safety clutch works correctly, the manufacturer's provided side handle must be attached to the machine. 

The risk of the core jamming is higher in wetter, winter months when the bricks and blocks have absorbed moisture. The moist dust can form a paste around the core body during drilling, increasing the risk of it getting stuck. To lower this risk, withdraw the bit from the hole periodically (almost completely, making sure that the core keeps spinning) and allow the debris to fall away and disperse. This should be done for every inch of material penetration. In drier, less problematic conditions, clearing the hole every couple of inches is sufficient, as the dust is less likely to bind to the core body.


  • Always use the appropriate PPE 
  • Select the right core for the application 
  • Wherever possible, use a dedicated diamond core machine with a mechanical or electronic safety clutch 
  • Always use the side handle provided with the machine 
  • Eject the pilot drill once you have drilled approximately ½” into the material 
  • During the drilling process, clear the debris from the hole by periodically, partially withdrawing the bit and allowing any debris to escape, reducing the risk of the core becoming jammed into the hole 
  • Apply, only sufficient pressure to keep the core in contact with the material surface and allow the core to do the work. 
  • Forcing the core will have a negative impact on the drilling speed and life of the core 
  • IF, the core does become jammed in the hole, remove the core manually. In these situations, using the power of the machine to free the core WILL result in damage to the machines safety clutch 
  • Continue to rotate the core whilst withdrawing from the hole


  • Use hammer action when drilling with a dry diamond core 
  • Apply excessive pressure whilst drilling. 
  • This will only reduce the drilling speed and potentially cause harm to the machine 
  • Make long continuous drilling motions without clearing the debris by partially withdrawing from the hole 
  • Drill hard materials such as cast concrete, granite or porcelain