I got at Herbach and Rademann (www.herbach.com) a double acting Air Cylinder with 2+ inches of travel. Run an air line to one of these (excellent insulation with vinyl or poly) and vary the pressure to adjust the height of the seconary... That is my plan, anyway. MPF the_machin_shin@hotmail.com ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com