Sinker EDM would be the quickest way to respline a stock shaft. And honestly we could send the shaft after to do a complete heat treat.
Yes that is how we would re-spline them, we would hard turn the ID (this would reduce sinker time) and then make the spline electrodes with the 4th axis on the cnc mill and edm sink the splines. Not really a fast way, sinker edm is slow, but it is just machine time. The reason I would wire cut the shafts is because that is what we have :tup:
What we would need would be the geometry and specifications of the splines.