(It's commendable to see you participate in these conversations, Brent......as well as just absorbing the information being discussed, whether or not you actively participate in the conversation. Most manufacturers are probably more personally engaged in design theory, rather than practical application. You are different.)
Hello Brent,
Concerning your comment about 99.9% of turners not being able to tell the difference in the material used for a lathe bed.....well, I think you are correct, and I also feel that I'm in that 0.1% category who could.....and, I also feel this is an important consideration for woodturners who strive to achieve the ever-elusive perfect cut in cross-grain bowl turning.
It goes beyond just the bedways, because the significance of the lathe bed is on the same level as how the lathe headstock and spindle is constructed....and the bearing arrangement between them. You are absolutely correct where the interaction of the cutting edge with the wood is of great importance, as well......and it's not just a matter of an out-of-balance condition of the turning block of wood......there are many other factors that influence the ability to achieve the "perfect cut".
@William Rogers has mentioned a few of those other factors......but, even they have their limitations as to how they ultimately influence the conditions that can lead to a perfect cut. My definition of a perfect cut is one that is devoid of any tearout, and requires a bare minimum of sanding. This completely eliminates the need for any power sanding at all. Hand sanding starting at grits at or higher than 180gt will make it possible to maintain a perfect geometry.....
and, it is precisely this perfect geometry which allows the turned details to be pleasing to the eye. Especially of note in bowl turning, is the grain of the wood alternates between long grain and end grain.......and that creates an alternating resistance to the cutting tool. Because of this, and in combination with any present vibration, it's been the bane of woodturners to create a tooled surface that is free of any tearout. When there is tearout, it requires coarse sanding, and coarse power sanding just can't get rid of tearout without destroying the perfect geometry that a tooled surface is capable of.
Vibration, I've come to have a very special relationship with.....and, controlling it through a combination of rpm adjustments, sharp tools, tool design, and technique has been my greatest challenge in woodturning. The manipulation of these multiple sources of input, in order to reach the best harmonic combination of these things, can't be learned in a seminar or class instruction......they must be mentally absorbed over time and experimentation in order to gain a complete insight into how these things are related to one another. I call this "spiritual turning", and it's something that seems the 99.9% of turners you mentioned are incapable of comprehending at their current level of understanding.
-o-