4 mm Carbide Pointed Flame burr works great for general carving. It also works well for inserting 4 mm acrylic lamp beads. The shape of the burr creates a pocket that hugs the bead in place. Using Diamond Glaze, or other adhesive that dries clear, secures the beads well. How deep you carve with the bit will depend on the thickness of the gourd and how you like the bead to sit.
