I finally got the corners rounded off after much contemplating on how I was going to do it. I do have to say having a rotary table sure makes easy work of milling things round, but there is a slight catch. I need more practice and patience to do a better job of setting the part up on the RT.
So without further a-do here are the pics.
I have run into the same problem as Bogs with having both the vise and the RT on the table. Both are very heavy and you don't want to put one on and take the other off and so forth. So I decided I'd leave both on and just move the one I'm not using out of the way. If the part I'm going to do is bigger and needs more room I'll take off the one tool that's not needed. Looks like it's time to invest in a hoist.

Believe it or not you actually need to do two true ups to get the part in the center. First the part must run on center of the RT itself and the it must be on center of the spindle. In other words the part needs to be located in the center of the RT table and then the "X" axis and "Y" axis must be on center to round the part.

The first cut was taken at .100" deep and 800rpm. So were the second and third cut. It was a bit noisy on the third cut and you'll see why further down the line.

Here you can see what the mill did when I took a .100" deep cut. Because the end mill was so long it vibrated and cut a bigger slot leaving a nasty blemish in my work piece. So I only took .050" deep cuts until I reached the bottom. It helped some. I kept the cutter about .005 off the bottom of the table.

Here's the big end all done with a nasty gouge out of it. Oh well, live and learn.

Here I'm lining up the small end with the plug I had made that I used to hold it to the faceplate of the lathe when I bored the hole in it.

Push down into the hole and clamp the part to the table. No need to indicate (clock) it in, right? Wrong.

Did smarten up a bit on this cut though. I used a shorter mill. What you can't see is that the rounding over is off center to the hole a bit. Guess I should have used an indicator to center it.

Here's the finished part, blemishes and all. It's still functional, just not pretty.

And here it is installed on the spindle.

That's it for the cotter clamp.
Maybe someday I'll make another one that is more visually pleasing, but for now this will have to do. It's functional.
Now I need to come up with a mechanism for holding the index pin. In the mean time I have some other small jobs that need to be done.
Bernd