Core drilling is commonly used to create the holes for routing cables or for placing anchor bolts. In addition it is used for cutting cores for checking the strength or quality of the in situ concrete (see also Testing concrete/Hardened concrete testing/Core testing for strength). A core drill bit consists of a steel tube with diamond segments brazed or welded on the drilling end, and mounted on a rotating shaft. Core drill machines can be operated in either vertical or horizontal direction and can be powered by electric, hydraulic or air sources.
Further information may be obtained from the Drilling and Sawing Association