Undercutting tool #15 is used to hollow out under hard to reach places.
When using with lathe, adjust tool angle often, and support tool firmly and close to turning wax to avoid chatter (which causes a corduroy like appearance).
For detailed info on Wolf Wax by Ferris, featured in these pictures, visit www.wolfwax.com. For info on Wax Carving Workshops and live demos by Kate Wolf, visit Wolf Designs.