Pins for very large structures are manufactured especially for the type of job and may have diameters of 24 inches or more and be several feet in length. For most types of jobs, however, pins are between 1 1/4 inches and 10 inches in diameter. The two types of pins commonly used are threaded-bridge pins and cotter

pins. (See fig. 1-52.) Threaded pins are held in place after insertion by threaded recessed nuts on both ends of the pin. Cotter pins are held in place by small cotters that pass through holes drilled in the pins. Washers and separators, made from lengths of steel pipe, are used to space members longitudinally on pins. Holes for small pins are drilled; larger pinholes are bored.