How important is it . . . (an osage question)

[Del the cat]

... why would a ring violation on the back do any damage?  What are the mechanics of that?

With Osage the dark rings have the strength of Iron, the pale rings have the strength of Chalk. That's why it's important to chase a ring, if you have violations it will just split apart along the exposed pale ring. (I can never remember which is the early and late, the pale or the dark)
You can feel the difference when you chase a ring...
Del

[Sidewinder]

Just to clarify, the light chalky stuff is early growth, the darker harder stuff is late growth.

I like a little tighter rings because it makes the fade outs look prettier. It has more striations. The thing I also have learned is that with any osage stave if you let it cure to the point where it almost sounds metallic when you knock on it, chasing the ring is a whole lot easier. The early growth is super chalky then and you are less likely to have tear out.  Also good lighting is key to following the ring.  Just my two cents.   Danny

[Springbuck]

  Exactly.   The fibers that you are counting on to not let the back break have been cut through at an angle.

It is possible to "decrown"  a stave or use a radial split, as the back, even with osage, but the goal is still to leave essentially full length fibers intact (remember that "grain" runs radially from the center of the log, AND sort of perpendicular to that line at the growth rings themselves).  But, that method is problematic. And the backs will be weaker, hence the bow wider, than on a chased stave.

[Springbuck]

The thing I also have learned is that with any osage stave if you let it cure to the point where it almost sounds metallic when you knock on it, chasing the ring is a whole lot easier.

Wow, yeah!  This is true of black locust, too.  You can feel it when it is very dry, because it seems to get really hard and rings like a bell or xylophone bar when you tap it.