Well if its show and tell time
This is a poly hub. I designed this one myself though of course the real credit goes to Jim Baxter who came up with the original idea. I tried to make it even simpler by making it from an easy to shape piece of triangular poly. I only uses single mounting bolts just tight enough to hold the blades and it all folds up if you whack the ground. This one has straight tangs but I now always use tangs with the hinge line offset by 15 degrees.
The shaft is 3/32 piano wire and the hub tube is just commercialy available brass with two small model car bearings inside.
Sean