Hi Dave,thanks for coming on board and the comments:
Well for starters Dave the White oak I used to fabricate the pressure box was milled from green logs, I did this on purpose so that the swelling of the box would not be excessive, when it eventually was exposed to water.
The problem was it was hard to determine just how much the timber was drying during the time from the milling process, the fabrication process and then of course the installation process, and most of these processes was in a heated environment
I realize that across the grain not much movement would take place especially with oak, but then there would be some, and the box is 36inches across solid wood, you can see what I mean.
On both sides of the pressure box run cast iron collars approx 36 inches in diameter, and these collars are on turned surfaces shouldered to bottom out at exactly the right spot and have cups molded in them in such a manner that the escaping water forces the shaft to spin in the opposite direction
You can see why the expansion of the box could be a real problem because these collars have a very small clearance and must run true so that they do not bind against the side of the pressure box
One of the problems associated with this type of power source is as the water passes through it also brings with it many fine particles and anything the right size can jam the wheel and stop the whole mill
I want to say this whole process was very interesting for me and my team, but in the end it ran like a top and is still running perfectly after approx 12 years now.