Diamond-groove (DG) drill bushings have a knurled surface that provides better resistance to axial and rotational forces than other styles of drill bushings. They are cast or potted in a hole using composites or resin. The resin or composite runs through the grooves during the casting or potting process to lock the bushings in place. The bushings' outer diameter (OD) is not ground, so their inner diameter (ID) must be kept accurately located during casting or potting. Type DG drill bushings install into fixtures to guide, position, and support drill bits, reamers, countersinks, and counterbores during holemaking tasks. The bushings keep the cutting tool from wandering or bending as it enters the workpiece, maximize chip clearance, and minimize the risk of marring the workpiece.