A straight nonfluid fitting with wrenching facilities on one end and external threads, other than pipe or hose series, on the other end. it has an unthreaded through hole in its axis which may be countersunk and/or counterbored on one or both ends. it is designed to accommodate a shaft, or the like, or used to reinforce a hole in a bulkhead, or the like. for similar items specifically designed for use in a stuffing box, see packing nut. for nonfluid items with an internal thread, see insert, screw thread; or adapter bushing. excludes reducer, boss; and items designed to accommodate a tube or tube fitting.