The set is accurate on most types of wood, fiberglass, PVC (polyvinyl chloride), and soft metals like aluminum. It is also capable of drilling perfectly contoured, smooth holes in soft, close-grained woods, particle boards, and floors. Designed for hinges, woodworking holes, and plastic products. For industrial hinge installation, woodworking and repair, model making, and spherical door tips, drawer tips, etc.The drill bit adopts a thorn cutting design, which greatly reduces the occurrence of hole wall chipping. Instead of scraping away the wood, the fluted cutting edge cuts it, preventing heat build-up and keeping the cutting edge sharper longer. Self-centering tips allow for precise actuation and the bit expels material as it cuts.A good choice for hole cutters, as the two-position prongs line the hole before chipping, providing a clean surface inside and reducing vibrations. It is very round, with a precision ground hex shank which prevents rotation in the drill chuck or bit extension. The drilling is highly accurate. The set engages the wood before the flat drill touches it, and the hole is very round as well.