Jigs are used in metalworking and woodworking when a workpiece needs to be guided along and kept in contact with a stationary tool. Fixtures hold the workpiece in place while the tool moves to do the work of cutting, drilling or shaping the workpiece.
Jigs and fixtures are especially useful when making a large number of identical pieces since the same jig or fixture can be used repeatedly. This saves time during measuring and setup, and ensures uniformity of the results. While adjustable jigs are available for some types of work, workers often make their own jigs to suit a specific workpiece.