What type of drill bit is characterized by its spiral cutting edge?

The drill bit characterized by its spiral cutting edge is the auger bit. This design features a helical screw thread, which helps in both drilling and removing debris from the hole as it cuts into the material. The spiral cutting edge enhances the bit's ability to efficiently bore deeper holes in wood and other materials by providing a continuous path for chips to exit, ultimately reducing friction and improving cutting speed.

In contrast, the Forstner bit is known for creating flat-bottomed holes with smooth edges, making it popular for woodworking tasks that require precision. The masonry bit is designed specifically for drilling into hard materials like concrete or brick, featuring a harder tip made of carbide. The step drill bit is employed primarily for enlarging existing holes and features a conical shape with a series of progressively larger cutting edges, but it does not have the spiral groove design that is characteristic of the auger bit.