Charlotte Core Drill
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Carolina Precision Core Drilling Inc

704-245-0119

Charlotte NC

Raleigh NC

Greensboro NC

How to lay out hole's for concrete core drilling.

lay out holes for core drilling by marking center of hole

When laying out holes for concrete core drilling everything relies on center measurements. A core drill bit is round so it follows logic.
Some things you might not know:
A) When possible use a lead #2 pencil to temporarily mark your core drill hole center's.
B) Be accurate. Once your core drill bit touches concrete the damage can not be reversed.
C) Then (when your sure about where the holes need to be located) use a permanent black magic marker to outline the OUTSIDE diameter of the hole. Do this so your marks are not washed away by the core drilling process. Wet Concrete is harder to leave a lasting mark on.

core drilling pattern for cored drilling operator to follow

The core drilling pattern marked on the reinforced concrete floor depicts the centers for each core drill hole that is needed, in the picture above 5" cores are needed. Each pattern is matches the outside diameter of the core drill bit to be used. If you mark out a 5" circle for a 5" core drill hole you won't be able to see the pattern when the bit engages the concrete making it tougher to be accurate with your core drill bit when core drilling.

Learn core drilling do's and do not's in our What is Concrete core drilling section

Questions you may have about laying out patterns for core drilling


Will the magic marker that I used to lay out the holes be seen?

Not if you use the right diameter circle to mark the concrete and keep the lines thins


What other marking devices will show up well on concrete?

Most dark colors of crayon, red welding pencils, some paint markers that are waterproof


Is it better to use a running total to layout holes with handrails, machine plating and columns?

Yes, if able to do so. Wehn marking each hole with a fixed measurement from hole to hole often you unknowingly add lenght or lose lenght as you mark the centers


Concrete core drilling with a diamond bit is the process of which one uses a large high speed drill to drill Clean, Non-destructive holes in concrete. The drill bit used to drill is hollow, which is where the core part comes in because instead of a regular hole like you get with a solid steel drill bit the center is left to be knocked out later after the desired core drilling depth is reached.

12 inch core drill shown.

Core drill operators in Charlotte North Carolina

Core Drilling can be either wet or dry.

Normally we in Charlotte, NC wet core drill most materials, and use a SDS roatary hammer drill when dry drilling.

Wet core drilling involves using water as a cooling agent as the core drill bit cuts a hole the material. Most core drill bits are embedded with bits of diamonds (in the teeth of the bit only) for cutting steel and other hard substances that may be in the concrete, brick or block you are drilling.

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