Fixing a Squeaky Platform Rocker

I have been having trouble with a squeaky platform, swivel rocker. I tried new bearings and lubrication of all wood parts but to no avail. I finally discovered where it seemed to be originating. There are two metal plates on each side which attach the lower stationary part to the movable part, held together by several screws, in my case four each side. These screws seem to become loose over time and cause movement in the two areas. I tightened the screws and saturated the space with silicone oil. Voila, no more squeak. The screws are somewhat hard to reach and require a blunt Phillips head screwdriver.