For my first grand daughter who is 5 months old. I can improve on the design since I free handed it without a pattern or drawing. It is made of cherry and finished only with salad bowl finish.
Can't tell about scale from the picture; but it looks like there might be a "choking" issue there. The federal government has a standard for toy sizes fore babies which is 1-3/4" or just a hair less.....can't remember for sure. The big end might be OK; but the small end could pose a problem. Other issue is the captive ring which could break off and be a problem.
Most baby rattles that I have seen are hollow and have something inside of them to make noise.
Louis: You have done a nice job on the one pictured; but maybe it needs to a ceremonial rattle for display only and another working model could be designed that is less of a safety issue?
Look at Nick Cook's web page, (nickcookwoodturner.com). He has a very good article on a baby rattle, and information about U.S. consumer product safety.