A thin-walled coring barrel with a high-performance diamond bit is attached to a water-cooled drill rig weighing between 1.8 kg and 3.5 kg. The drill rig pushes the drill barrel forward concentrically thereby avoiding bending forces during drilling. A special plastic coupling is used between the electric drill and the coring barrel to reduce vibration of the bit, ensuring a long life for the diamond bit and a smooth core surface. The drill rig is kept securely perpendicular to the surface by adjustable clamps anchored to the surface or by a suction plate. The end result is a quickly drilled core that has a smooth surface, accurate diameter, and drilled perpendicular to the surface. Two versions are available: CORECASE CS-75 for a 75-mm core diameter and CORECASE CEL-100 for a 100-mm core diameter.