Since we are on the subject of volute carving I thought I would share this little snippet from a video with Mack Headley on The Woodwright's Shop that discusses classical carving in the 2008-2009 season. Here is a link to the video and if you move the video up to about midway (14:00) there is a nice overview of a simple practice for carving a volute.
Just to quickly hit the high points you will see that he hand draws the volute by eye. Based on a 1/2" center he graduates in 1/8"s of an inch per half a circle radiating out form the center as it extends. Each chisel that he choses is used for a half of a circle within the volute. Notice how he walks the chisel when defining the line and how the edge is sharpened in an arch aiding in a natural motion of the hand while moving along the arch. He notes that the chisel sweep that defines the line of the volute will be used to excavated the adjacent area towards the center of the volute.
Some nice points to use in practice to further simplify the thinking behind making this fundamental carving easier to grasp and allows you to feel free to work with this element within your own designs.
I have included a link to a post from Peter Galbert's blog for a method for drawing a volute by eye on a handhold.