It was made from the stump of a tree (ideally, white oak or pine) burned hollow, scraped clean and polished. You aimed to make your hollow an inverted conical shape — the fire could be guided by holes drilled in the stump.
Ideally, the tree stump would have a healthy sapling tree nearby, or a tree branch.
If so, you’d tie a block of white oak to the sapling or branch. Otherwise, you’d make a sweep coming off a post and hang the pounder off that.
You worked the device like a piston, with whatever you’d hung the pounder on acting as a spring to lift it back up for you to ease the work. Still, it could take half a day to grind up half a bushel of corn into cornmeal.
They were used in Canada and in America. Some small towns would make a public one for everyone in the public square.