Picture of the hub type I use is included on my webpages http://www.geocities.com/tintrax/page6.html (copy & paste if necessary)
Note also the nuts & bolts that clamp things together. Contact cement used too. In the event of a hinge breakage after a bad landing the hub can be prised apart and a new polypropylene hinge installed. Fifteen degrees delta angle, blades at zero incidence relative to each other, the delta angle takes care of incidence alterations automatically in flight.
I am not saying this is the best hub, just the simple cheap design I have settled on.