Ursus: Some wavyness is OK, even grain that runs off, if it doesn't go all the way across the shaft, will probably be OK.
Luke V: Good point. I did get a batch of Doug fir a while ago that was very brittle. Fella I got it from said he doweled them from 80-100 year old timbers acquired through some sort of building demolition. I think the stuff was just too dried out. That's the only time it's ever happened to me, but perhaps Doug fir is susceptible to overdrying and becoming brittle.