 Although they are usually used to attach pipe and fittings to mechanical supports in buildings, they do not connect the pipes to each other.Fasteners commonly used with piping are a stud bolt  with nuts (usually fully threaded, with two heavy, hexagonal nuts); a machine bolt and nut; or a powder-actuated tool (PAT) fastener (usually a nail or threaded stud, driven into concrete or masonry).A threaded pipe has a screw thread at one or both ends for assembly.