Select two dowel rods that are straight and free of cracks and knots. You can use wood, aluminum or fiberglass. Cut them down to 12 or 15 inches long, depending on your preference.
Using your electric drill and a 7/16-inch drill bit, drill a hole through each rubber ball.
Tie the yarn around the rod where the base of the ball will set. Wrap twice around the rod to cover your knot.
Pull the yarn through the rubber ball as you insert the rods into the ball. Coat the inside of the ball and the end of your dowel with glue before inserting halfway into the ball.
Hold your mallet at an angle; wrapping off center, follow an "X" pattern. Do not cover the hole at the top of the ball.
Cut the yarn when you are finished wrapping, leaving 3 inches to spare. Tie a knot in the end of the yarn and coat the inside of the hole with glue. Use a narrow tool like a pencil or a screwdriver to guide the end of the yarn into the hole.
Secure the yarn by stitching the last piece to the ball at the top.