Leeson Field Installed Adjustable Motor Slide Base Heavy gauge steel mounting bases simplify the installation of motors and make the tensioning, maintenance and replacement of belts a simple efficient task. Fabricated from sheet or steel plate, then primed and finished in a gray rust and corrosion resistant oven-baked finish. - Gussets and reinforcing channels on larger units and continuous seam welding on all units give these bases strength and durability for a long life. A single (215T frame and smaller) or double (NEMA 254T frame and larger) zinc plated adjusting screw is provided.