Thank you for your response. Attached are 3 jpegs...

The "basic setup" is just to show how a mock up of what I am trying to do looks like... so you can see my general issue. Now in a complete set up I would have the wooden log with a 1 inch wide slot cut just deep enough along its length so that the bridge blank would match up with a 3" diameter circle. Then as the A-axis rotary turns it would cut the curve onto the wings of the bridge. The "log" which is made of Spanish cedar is very light... slightly heavier than balsa, is 3 1/8" in diameter. Now my first step is to turn the log itself and true out the log to be an exact 3" diameter. So the log must turn at a speed that is slow enough that the end mill can keep up with it. The mill end spindle runs up to 24,000 rpm and I simply turn it on manually for the time being while I am learning. So I have to have the rotary turning at one speed and then the y-axis progressing down the length of the log at another speed. All of this is just to get the log trued out. Then I start facing the real issues of the bridge factors. Now I am brand new at all of this and the learning curve is a bit daunting...but I will hang in there.

Now as you see, there are two slots of different widths and depths in the middle of the bridge. The thinner of the two holds a piece of bone, (used to be Ivory, but we need our elephants now so its bone), and that slot leans slightly toward the back of the bridge to hold the bone at a slightly stronger position relative to string tension... so the rotary could then be moved to whatever portion of a degree etc., that would give the slot its proper back-tilt.

The transition from the wing of one side to the wall in the middle part of the bridge has to be ninety degrees so I do not have a good image of how that could be done with a ball end mill.

I am open to everyone's considerations and ideas on all this. Right now I need to figure out how to get the lathe aspect to turn at a slow speed, and then have the mill end move down the length of the log so that it cuts the log and trues it out so there is no wobble that then translates to a wavy surface on the curve of the wings.

Sincerely guys, bob