Thanks Tim, I've been planning on doing this axe for about ten years. Just now getting to it.
Nord, yes there is a piece of leather between the head and handle. It acts as a gas seal and also keeps the head from getting sloppy loose when the wood shrinks from lower humidity. I prefer to use brain tan over any other kind of leather. The caps on pipe axes were for decoration and this one also seals off the hole at the top of the handle. Some axes have the hole through the end caps and are plugged with a decorative plug. Pipe bowls on axes were made many different ways screw in, brazed on and one piece.