A free hand MAY be ok depending on age and severity of action and what other punishments have been attempted.
But ANY object (just my opinion) is over the top. So any belt (had it used on me), kitchen appliances (had them thrown at me), "switch", branch, stick, shoe, spoon (my mother inlaws favorite tool).... Is too much.
If your a kid and you can't get the point with a smack on the butt then why would you get it if I smash you with a stick repeatedly until your a bumbling mess?
Side note: corporal punishment is a family. I think if you ask around, those that are in favor of a "a good beating" will have had them applied to them when they were children. So they assume "hey I turned out ok" so it must work for their kids. Very wrong.
There have been many advances in child discipline. For example anyone else use the counting game and time out thing? I don't know how "new" it is, but I certainly never heard of it growing up nor any of my friends did either. So child discipline is like any other thing.
Why be like a cave man and grunt while you beat them with club. Try acting a bit more civilized and use non aggressive means. Just saying...