Kip, I had a similar problem when I first used mine. Then, as Woodbow suggests, I used a pre-shaped shaft as a template to set the blades and my problems were solved. I now have a couple of old /broken tapered shafts saved as templates in the event of a blade change.
In an earlier thread, there was mention made of tired arms and hands. Well, I'm of the "energy-efficient" variety (otherwise known as lazy!) and use a drill to grind/cut the tapers. Provided you advance the shaft slowly and spin it adequately quickly, the end result is the best I can achieve.
Hope this helps
Mark

"tread softly and carry a big stick" - acknowledgements to LandRover & FDR.