Scott,
I have in my basement a used Forespar Ultra UXP-250 fitting #304050
It fits a tube with 1.87" ID. You could use this and have a piece of Delrin turned in a lathe to make a sleeve for the aluminum pole. It will need new Amsteel loops installed.
You can have it for $50 plus shipping.
ps - you can also make the sleeve with raw Delrin stock and a drill using two circle cutters. Drill the outside diameter first, then drill the inside diameter.