Cut a one-eighth inch wide, one-half inch deep hole into either a rubber ball or a wooden ball. Use a drillbit with a one-eighth inch drill attachment and put the ball between a set of clamps. The choice of material is up to you. A wooden ball will have less bounce and sound harder. A rubber ball will provide more bounce and give a softer sound.
Pour a small amount of glue inside the drilled hole. Insert a one-eighth inch dowel approximately seven inches long into the hole. Let it set for 15 minutes.
Insert a push-pin into the top of the mallet head. Make sure it is in line with the dowel horizontally. Don't push the pin in all the way. Leave about two millimeters free.
Take the material you want to work with and wrap the mallet head. Start by tying a tight knot at the base of the ball, wrapped around the dowel. Wrap the material around the pin 180 degrees and then wrap around the dowel again on the bottom. Wrap around the head again, but this time move the material just to the left of the initial thread. Continue until the entire ball is wrapped in the material you have chosen.
Tie a double knot at the top of the dowel and remove the push pin. You now have a custom made mallet.