Set screw size is 1/4-20 Use 1/8" hex wrench to tighten.
1. Remove the three screws that secure the flat cover to the top of the base enclosure at the head end. The photo shows the screws under the trim. Remove only one from each side and one at the head end.
2. Align the hole in the top frame with the hole in the scissor and tap the 1/2" diameter rod through both weldments. Make sure the rod is rotated so that the flat spot is aligned with the set screw in the collar.
3. Remove the set screw from the welded collar at the top end of the scissor. Apply a drop or two of blue thread locker. Tighten the set screw against the flat surface on the rod.