Hi all!

I am currently trying to incorporate NURBS modeling in my workflow as it seems to be better suited to most of the stuff I have to model. Still, I can't seem to wrap my head around this... I am trying to model a pelton wheel:

http://www.lingenhoele.at/de/turbinenbau/Peltonlaufrad
http://www.cink-hydro-energy.com/galerie/turbiny/galerie/pelton/pel8_big.jpg
and much more if you do an image search for "pelton wheel"

I made some progress but I am having problems with the sharp crease in the middle and the way the round part blends into the square part where it is fixed to the axle.

If somebody could help me out and give me some tips how to approach this it would be much appreciated.
Thanks!