Never made one out of wood, but for $3.95 at HD you can get a 3 foot 3/4" aluminum Rod. Cut it to the length you want (with a 3 foot section, you can make several lengths), turn it to the diameter you want, drill a hole and tap the center of the rest. Then cut a post to the length you want and turn it till it fits in your holder and thread the top to fit the rest. Very easy to do with the lathe.
I know guys that have done this with a brass grounding rod,too. I've haven't done this, but brass also cuts easily on the lathe.