took a test cut across a 1/4" BRASS ROD
I could not believe my eyes when I read the vernier; "NO" taper at all 0.247" dia across the lenght of 95mm; I'm flabbergasted I really did not expect that; a bit of tweeking yes; but not dead on first try

The center sounded very quiet and had no residual vibrations to add to the test cut; with a cut of only 0.0015" at 1700 rpm I expected a bit of vibration
I'm still not happy with holding it so far out in a drill chuck (but it is a very good chuck) but hey if it works what the h*ll