[ fixing devices; namely, nails, screws and bolts; fastening devices; namely, clips; connecting devices; namely, plates, rods and pins; spacers and inserts; namely, shims and pads; and reinforcing liners of common metal for retaining fasteners in holes, all for use in engineering, ] helical coil inserts common metal for increasing the pull-out strength of screws inserted into deformable materials, [ screw nails of common metal ]