First and foremost make sure there are no tree limbs within 10' of the feeder in any direction. I had a raccoon that was using it's weight to make a branch drop down to within a couple of feet of the feeder and then free falling the rest of the way.
The pictures show the rest. A 2' section of 8" stove pipe with the upper end closed off with a 8" circle of wood or plywood and fit inside the pipe and fastened with screws. Drill a hole through the center of this that will fit a piece of 3/4 inch conduit long enough to get it to the height you want it above the ground. use a hose clamp on the conduit for the under side of the wood to rest on. Above that put the metal cone. Leave enough room for it to swivel on the support that comes with it. Makes it very difficult for anything to climb over it.
That takes care of the squirrels and raccoons, but the critter I had the most trouble with were the doves. The only way I was able to finally defeat them was to use wire fencing for a frame and cover that with the screening they sell at home depot for keeping leaves out of gutters. It took a few tries to get the openings size right. You have to have it big enough for the song birds to go through but small enough that the doves can't hang on to the side and stick half their bods through and get at the seed. They are like vacuum cleaners and will suck a feeder dry in a day.
This feeder was here when we bought the place and I modified it as shown. It was a good feeder when it was new, but it is starting to show it's age. It's made of cedar, so I have kept patching it back together because it holds up better to the weather, but I think I am going to have to try and build a copy of it before long.
Anyway, I have been using this thing for two years now as shown and have not lost bird seed to any of the aforementioned critters, so I think it is working well. The birds seem to like it. I have counted as many as 20 birds on it at once if it has snowed and food is hard for them to find.
