Thank you so much for the compliments. I also tried using a cardboard tube and using my thumb to make the diagonal winding pattern. This is the video that I later aspired to use it's method.https://youtu.be/oGaA92IjXDg. It shows how simple the "wooden dowel" can be: she says the grooves to tie the tail on to get started are unnecessary and add a needless step at the end. And some nostepinnes on the market have a tapered neck between the yarn end and handle that the yarn could slide into. Another consideration is length. Most I found on the market were 12-18" but I had watched a Scandinavian knitting podcast where the host used one not much longer than the width of her hand. Plus the shorter 5-6" ones fit nicer in your knitting bag yet can hold most skeins. Some people cut off the end of a broom handle or you could check out any children's building blocks or wood marble roll sets you might have stored for a good diameter.
I love the yarn winders my son made me. He normally lathes pens out of beautiful exotic woods and uses an 18 step sanding and finishing process to make a durable, hard, shiny, and smooth surface. He applied this same finishing technique to the yarn end of the yarn winder to not snag the delicate yarns (even short fiber of unspun yarn). I like the cubical handle juxtaposed against the cylinder which also acts as a hard stop to push the developing yarn ball against to help shape it. I like the look and feel of the hard finish and it highlight the beauty of the wood. It is like a little piece of art. As an aside he made a coffee scoop that had coffee beans embedded in the acrylic last week. You could smell coffee as he lathed it!
He would be glad to make one for you or you are welcome to copy his design. 6" total length and 3/4" diameter. Cube handle is about 2" long and easy to hold and rotate between your thumb and finger tips.