Oh, man. I'm with J. Tiers...this isn't something to start out on. But if you're crazy enough to want to who am I to stand in your way.
A friend of mine once machined a propeller, which is sort of the same idea. He did it by stacking up two rotary tables. One he used to index to each blade (for a 3-blade prop, it would be every 120 degrees). Then he used the other to add an incremental index to a position on a blade. At the given position, he milled a straight line with a ball end mill at a predetermined depth. By milling at successively greater depths at incrementally greater positions, he created the blades. All this took a LONG time.
That's a pretty sketchy explantion and I've probably left out some critical details, somewhere.
That method also assumes the blades don't "wrap under" each other, i.e. the entire blade surface is visible if you look from the top. That might not be true of a turbine runner.
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