or maybe he is righ?t in that case i will start making nuts for my leadscrews out of brass as it obviously is a good material to use no? because plastic nuts on aluminium leadscrews would not be a good idea either and bronze would definitely not???????????????? (am joking here just in case it is taking literally)

George i am not sure where you get your facts from as google has the monoply on the answers. For an informed view checkout what the pros do please? servo's (the type in model aircraft) have been meshing aluminium and plastic gears for years.