The great thing about cob is its low-tech nature. You don’t need many fancy tools to work with the medium. Cobbers thumbs are useful wooden hand tools for pounding cob into place on walls, and “stitching” the material together. The fat, blunt ends are good for the pounding, and the pointed ends are useful for weaving different layers together.
You can make these with any old scrap wood. I made these from a downed black locust branch, using just a utility knife and a bow saw.