"RUNOUT" - what is it, what can you tolerate?

Join Rod for some shop talk around the issue of "runout" in a handle. What exactly causes runout? Will it weaken a handle? can you do anything about it, or is there a certain tolerance that you can get away with? Rod shares his 30+ years as a handle craftsman to explain what it is, what to look for and avoid - and when you should leave the handle on the shelf.