Diamond core drilling utilises an annular diamond-impregnated drill bit attached to the end of hollow drill rods to cut a cylindrical core of solid rock (or masonry). The diamonds used are fine to microfine industrial grade diamonds. They are set within a matrix of varying hardness, from brass to high-grade steel. Matrix hardness, diamond size and dosing can be varied according to the rock which must be cut. Holes within the bit allow water to be delivered to the cutting face. This provides three essential functions; lubrication, cooling, and removal of drill cuttings (in this case, fine slurry), without which drilling cannot continue. The core is retrieved via use of a core lifter, a hollow tube inserted into the core barrel which slides over the core as it is cut. A tool is sent down and locks on to the core lifter, and pulls the lifter and its core to surface. Once complete it leaves a neat circular penetration. This type of drilling is one of the only ways to drill through heavy steel re enforced concrete.
The procedure involves bolting anchor points of the drilling mast to the concrete surface to be core drilled. Or if the surface is a finished surface ie tiled floors walls or painted finished walls, a vacuum pad and pump is used which does not require bolting anchor points into the surface.
During drilling with a circular drill bit, water from a hose connected to a tap is flushed down the hole to capture dust, remove slurry and keep the drill bit cool. This procedure is common for all core drilling equipment, despite the fact that most equipment is electricity driven.
Core drilling has a large range of applications where a circular holes is required completely or partway through a floor or wall made of bricks, blocks, stone or concrete, these may include:
- Air conditioning pipes
- Electrical conduits and cables
- Bollard installation
- Plumbing pipes
Core Drilling have various Depth and Sizes
Core holes can be drilled to almost any depth starting at 5 mm deep.
Core holes are available starting from 14 mm up to 400 mm in diameter. They can go larger pending on the requirement.