A headless fastener not exceeding 12 inches (304.8 mm) in length, threaded externally on both ends with threads of the same nominal diameter. the maximum diameter of the unthreaded portion must not be greater than the nominal thread diameter plus 0.020 inches (0.508 mm). the unthreaded portion must be without locking or wrenching provisions. it may be thread relieved. see also rod, threaded end and rod, continuous thread.