Thanks Jerry........
Al.....I am pursuing my own goals in woodturning. It's ok if you have other goals in mind. This is only a discussion.
For Robo and Al......perhaps you are not acquainted with the advantages of having surfaces as close to geometric perfection as possible. I tried to explain this, but maybe I'll put it in another way. It has nothing to do with the curves and form......sanding will not destroy form or curves to the point where it's an obvious distraction to the eye......unless it's just way too excessive.
If you have two surfaces that meet at a corner, the further from a perfect circle the mating surfaces intersect, the more apparent it will be.....because any variation in the geometry will cause the two surfaces to not intersect at exactly the same point throughout the circumference of the intersection......there will be places where the "corner" doesn't match perfectly. This is very visible to the observer, so the only thing that can remedy the problem, is to round over the corner equally throughout the circumference of the intersection.
A perfect corner is visually aesthetic to the eye, and perfect corners can only be had by perfect geometry.
If a surface is unevenly sanded, due to sanding alternating long grain and end grain.....and, a turner wishes to use detail groove(s) on that surface, then the detail will not be visually appealing to the observer if the depth and width of the groove is uneven throughout the entire circle on which it exists. The detail groove will look more perfect to the eye, and therefore more visually appealing to the observer, if the underlying surface is more perfect in it's geometrical shape. The only way to minimize distortion, is to minimize the sanding.
Both of these things become more visually appealing to the eye, the more perfect the underlying geometry is.
The only way to make it happen is a very sharp tool, a steady hand, and some learned skills in doing it. If Jerry is starting sanding at 320, then his resulting corners and detail grooves will likely look sharp and cleanly done......the observer will notice this, whether he conscious of the inspiration, or not. The result will be aesthetic appeal.
Of course, all of this applies to my style of turning, and there are other turners who do very well with sanding more than I can except for my own work.
Here's a couple of quick examples:
Photo 1 is a zebrawood bowl that has an intersecting corner of two surfaces just outside of the foot. This is a difficult intersecting edge, because the angle (cross section) of the corner is very obtuse. The closer to 90° the easier it gets, but this one is more like 150°. For such an obtuse angle, the only way the intersection will be a crisp sharp corner, is if the geometry is as perfect as possible.
Photo 2 is a Brazil cherry bowl with multiple detail grooves. The grooves pass through long grain and end grain. Any variance in the geometry caused by sanding will in turn cause the detail grooves to be deeper on the end grain, and shallower on the long grain. The width of the detail grooves will also vary throughout the circumference of the cut. The only way to minimize this, it to minimize sanding. I suspect most turners avoid detail grooves, because detail grooves that visually vary just plain look bad. Detail grooves that are cleanly cut, and have minimal variation look pleasing and aesthetic.
ko