A buffing wheel won't do it if you're starting with a machine finished post. You neet to smooth out the grooves first. I use a 1/4 sheet pad sander and medium fine paper. I smooth the scratches from the sander with steel wool and then I buff it on a cotton wheel with rouge. You can do the same thing by hand, it just takes a lot longer. Figure out how far you are going to insert the post and don't sand below that point. I cover the part I don't want to sand with duct tape.