I used the wooden centers from the baby rattles to make a yoyo. I rounded over the edges with a router, using a 1/4″ roundover partially set for the inside and a 1/2″ roundover for the outsides.
The two sides were chucked in to my drill press using a bolt. This let me sand them smooth quickly and afterwards I hand sanded with 220 grit.
The halves are joined with an oak dowel which was trimmed with a flush cut saw. I used some spare kitchen twine instead of a real yoyo string, but it works well.
The yoyo works but does not sleep long. I think using some silicon lubricant or adding a sleeve over the dowel will help. I will glue the halves on the dowel once I’m happy with the performance.