Of course, a power drill is useless without accessories. These pieces, which are designed to fasten into the chuck, can accomplish a surprising number of tasks. The most common kinds of accessories are drill and screwdriver bits.
Drill bits, like the drills that turn them, come in a variety of shapes and designs. The most versatile of these is the twist bit, a cylindrical shaft with a cutting edge wrapped around it like stripes on a candy cane. These bits typically range in size from 1/64 inch to 1/2 inch and are commonly used to bore holes in wood and metal. Spade bits are the cheapest and most effective way to drill larger holes in wood. The sharp, flat end of these bits is able to scrape away the surface of the wood as it cuts, creating holes between 1/8 inch and 2 inch in size. Brad point and Forstner bits are specially designed to drill cleaner and more precise holes, but they're generally more expensive than twist and spade bits. Drilling holes in concrete or masonry requires special tungsten-carbide-tipped bits; impact drills are especially well-suited for this task.
There are also many different types of screwdriver bits. Phillips head bits are the most common, as these kinds of screws are used extensively in construction and home improvement applications. Other kinds of screwdriver bits include flat head, torque, spanner, tri-wing, hex and torx. Each is a variation on a simple concept: the bit is shaped to fit into a corresponding slot on the head of screw so it can be effectively tightened and loosened.
With the right accessory, drills can emulate almost any tool in the shed. Drum and disc sanding bits can sometimes be used to do the work of much larger and more expensive machines. Other bits can polish, cut or grind materials; larger attachments can even stir paint, mix concrete and serve as a handheld earth auger. Kits are available that harness the power of a drill to create makeshift machines like a lathe or a water pump. While these uses show the incredible versatility of power drills, their specialty is still boring holes and driving screws; they aren't perfect substitutes for the tools they're meant to imitate.
Now that we know all the parts and accessories associated with power drills, let's learn how best to use them.