If you're hanging pictures or putting together a bookcase, a hammer is a perfect tool: simple, cheap and entirely effective. But if you're building a two-story house, installing hardwood floors or running your own furniture repair shop, you may want to spring for a nail gun. These powerful machines launch nails at high speed, fully embedding them in a piece of wood in only a fraction of a second. Obviously, such a machine can save you hours of toil and sweat. They take almost all of the work out of nailing.

Photo courtesy Hitachi Power Tools
There are a wide range of nail guns on the market today. Different designs are configured for specific nail sizes and applications.

In this edition of HowStuffWorks, we'll find out how these popular machines launch nails at such astounding speeds. As it turns out, there are a wide variety of nail guns on the market, employing a range of physical principles.