A core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core.
Core drills used in metal are called annular cutters. Core drills used for concrete are generally called Diamond Core Drills and are water cooled. For drilling masonry, carbide core drills can be used.
The earliest core drills were those used by the ancient Egyptians, invented in 3000 BC. Core drills are used for many applications, either where the core needs to be preserved (the drilling apparatus used in obtaining a core sample is often referred to as a corer), or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit. This is the reason that diamond-tipped core drills are commonly used in construction to create holes for pipes, manholes, and other large-diameter penetrations in concrete or stone.
Core drills are used frequently in mineral exploration where the coring may be several hundred to several thousand feet in length. The core samples are recovered and examined by geologists for mineral percentages and stratigraphic contact points. This gives exploration companies the information necessary to begin or abandon mining operations in a particular area.
Before the start of World War Two, Branner Newsom, a California mining engineer, invented a core drill that could take out large diameter cores up to 16 feet in length for mining shafts. This type of core drill is no longer in use as modern drill technology allows standard drilling to accomplish the same at a much cheaper cost.
Core drills come with several power choices including electric, pneumatic, hydraulic (all of which require power sources, such as a generator).
Diamond drilling has revolutionized the mining industry and directly resulted in the discovery of many minable orebodies that would otherwise have gone untapped. Before the introduction of mainstream diamond drilling, mining was still primarily dependent on finding outcrops of rock, with little information available about ore concentrations below the surface. Diamond drilling allows for the removal of solid cylinders of rock (core) from deep within the earth.
The term diamond core drilling comes from the “diamond bit” drill used during this process. This drill bit is made up of a group of small, industrial grade diamonds set into a metallic, soft matrix. As the ground is drilled this matrix will wear away and expose more diamonds.
The diamond bit is then attached to a drill rod which measures to about 10 feet in length. More sections of pipe can be attached to the top of the drill rod, allowing greater depths to be drilled as needed. Therefore, the number of rods attached to the top of the drill rod will determine the depth that can be drilled. Within the drill rod a core tube is attached to a cable by a latching mechanism. The core tube is lifted to the surface using the cable to allow for the removal of the solid core.
When developing and improving our core drill motors, drill stands and diamond bits we look at the whole system, and at every part, to find ways to make skilled drill operators work even more efficiently and effortlessly.
Our best reward is when customers tell us how their new core drill system has helped them nearly double their production rate. We are not surprised. Whatever your demands are when it comes to core drills, it’s the focus on productivity that makes a concrete core drill system stand out.