This chapter is devoted to the analysis and design of power screws, threaded fasteners, bolted joints in shear, and permanent connectors such as rivets and weldments. Adhesive bonding, brazing, and soldering are also discussed briefly. Power screws are threaded devices used mainly to move loads or accurately position objects. They are employed in machines for obtaining motion of translation and also for exerting forces. The kinematics of power screws is the same as that for nuts and screws, the only difference being the geometry of the threads. Power screws find applications as motion devices.

The success or failure of a design can depend on proper selection and use of its fasteners. Afastener is a device to connect or join two or more members. Many varieties of fasteners are available commercially. The threaded fasteners are used to fasten the various parts of an assembly together. We limit our consideration to detachable threaded fasteners such as bolts, nuts, and screws (Figure 15.1). General information for threaded fasteners as well as for other methods of joining is presented in some references listed at the end of this chapter and at the websites www.americanfastener.com and www.machinedesign.com. Listings of a variety of nuts, bolts, and washers are found at www.nutty.com. For bolted joint technology, see the website at www.boltscience.com.

Analysis of riveted, welded, and bonded connections cannot be made on as rigorous a basis as used for most structural and machine members. Their design is largely emprical and relies on available experimental results. As with the threaded fasteners, rivets exist in great variety. Note that, while welding has replaced riveting and bonding to a considerable extent, rivets are customarily employed for certain types of joints. Welding speeds the manufacturing of parts, assembly of these components into structures, and reduces the cost compared to casting and forging. Soldering, brazing, cementing, and adhesives are all means of bonding parts together.