I thought I’d just add a bit about my stools. For the most part, I make these stools to order. I make a milking stool which is about the height of a chair (16″ or thereabouts) or, depending on how it will be used, a little shorter.
The taller stools begin at about 20 or 21″ tall and can be made up to 29″ tall. I use a variety of domestic hardwoods to make the stools, and I often combine different woods in order to contrast the colors and grain patterns. I vary the turnings on legs and stretchers to add visual interest.
The stretchers are joined to the legs with straight through wedged mortise and tenon joints. I often use wedges of contrasting woods to emphasize the joinery.
The legs are joined to the seat using a tapered through wedged mortise and tenon joint. This means that the tenon is larger on the bottom than it is on the top. Thus sitting on the stool exerts force on the joint that would tend to tighten it rather than cause it to fail. (In practice, I don’t see this joint moving much in use.) I also use a wedge in these joints that is wider than the tenon. This keys the joint, making it resistant to failure from twisting.
Here’s a set of stools made for a friend’s house at Bald Head Island.