An empty 12-pack of soda was the perfect size for my hand saw, and thin enough to get a standard hole-punch through for the tip. I marked the first hole with my utility knife, punched through a single layer of cardboard, then used that as the template to position the second hole correctly. Sealed the guard with paper tape, because my clumsy self would likely just scrap my hand on the staples instead. ;-)
A friend's father made me something similar ~30 years ago and used finish nails. Just enough of a head to keep the yarn from slipping off.