Screws (Useful Machines)

What are screws? How do screws work? Can a screw be used to lift a car? For the answers to these and many other questions, read Screws. See how screws are used to hold things in place. Discover how screws are used to make holes. Find out how nuts and bolts work like screws. This book describes what screws are and how they work, different kinds of screws and their uses, and other facts about screws.