A friend just had a newborn….
Rattle designed (but not tested) to meet
1 3/8 diameter x 4″ long (used 2×2 blank)
Basswood: ideal as it is light and close grained (otherwise the rings tend to break). Holds up well to moisture.
Finish: mineral oil, (Baby oil can also be used)
Warning: infants should never be left unattended and unsupervised with any rattle.
Note: You manufacture, provide and use rattles at your own risk. This post in no way provides assurance, warrants or implies that this rattle design is safe for use.
See photos below: