Minihawn,
Go to any hardware store and get some 1"OD x 3/4"ID x about 1" steel bushings, get some 3/4"OD x1/2"ID bronze hat bushings to fit them, and get a length of 1/2" drill rod for the pins. All of that stuff for two hinges will not come to $20. Cut and drill some plate hinge arms to suit your application and weld it all up. When you weld it, assemble the entire thing, clamp it down, and weld it that way. The pin will keep it all perfectly aligned. The bronze bushings are oilite, meaning that they are impregnated with oil, and the heat from welding will cause some to seep out, but it will not matter. A hinge constructed this way will have zero play in it and be plenty strong. They can be done in aluminum the same way but you will need to get the aluminum bushings from someone like Tube Service Company. I have always wondered why they are $400 or more a pair, when they are available at all.