Ok, which is going to give the best finish turning 416 (or 300 series for that matter) when you have to creep up on the final dimensions in order to reduce work piece deflection.
A vertical shear (which is what I used) leaves much better finish than the roughing tool I was using the other day on that taper, but it took 3 passes to get "decent", and I still had to spend a fair amount of time with multiple grades of emery cloth to get a smooth brushed looking finish. Its hard to creep on on too because you have to resharpen it or atleast move it up or down on the tool post atleast once in that time.
I originally ground the vertical shear to get a "better" finish on mild steel. It does that, but better is relative.
I did the usual Google searches for getting better finish results turning stainless and a "round shear" came up in one result, but the PhotoBucket virus ate the pictures so I am not sure what they were talking about. Some search for that term came up with what looks like round carbide turning inserts for wood. They also look a lot like the round inserts used on some face mills.
The other result I cam across were a few conversations about using a radius nose tool. Some argued they got great results with a veyr small radius and a large feed. Others said quit the opposite and said to make the radius nose on a finishing tool as large as you can and use a small feed. WHAT!?!?
Yeah, I have discovered the harmonic you sometimes get in the middle of a long span. For straight pieces a steady rest was recommended by some guys, but that doesn't work for a taper. One guy said he wrapped a couple lengths of chain around the work and hung a five pound weight from it. Dang-it. Wild. Note: The very light passes to finish with the vertical shear did not seem to develop the harmonic resonance, but I was turning really slow.