If you are talking about something like this then check for METRIC Ball Nose End Mill. They are for metal but should beable to use for wood or for what ever.
https://www.redlinetools.com/CatSea...LLfT6PRqdqbJCAKV6TXuMPCkm06RitgEaAleNEALw_wcB
https://www.redlinetools.com/CatSea...LLfT6PRqdqbJCAKV6TXuMPCkm06RitgEaAleNEALw_wcB