The engineer didn't even analyze the scarf joint, or at least he didn't include the bending stress graph in my booklet, sorry about that.

The two videos that follow are showing the bastard valley bent systems, of which there are two, each mirror-images of each other.

Each bent is comprised of a tapered octagonal bastard valley (tapering from 15" to 12"), a tapered knee brace, a horizontal tie, a "pacman" 20" diameter log post, 2 12" diameter posts with flats cut on them 7* off of bent centerline plumb (these flats define the stairway opening, which cuts across both systems), and a baby post to cut down the span of the bastard valley.

Other than the barrel bolts we are using to hold the tie to the posts, and a lag shot into the bottom end of the knee brace, everything else is all wood joinery.

Each valley sits on 5 bearing points and the main peak of the house is the centerline bearing point for 10 different timbers. As you can see from the animation, the bastard valleys sit on the ridges that sit on the main, 24" diameter, Old Glory post. So, it goes without saying, even though I am going ahead and saying it, that the precision required throughout this system was off the chart. I think these bastard valleys in particular (each with 25 notches) will be the most complicated and challenging, and expensive, pieces of wood I have ever been involved with. Not to mention setting up the interior posts so that, when raised, their flats that define the stairway are not only where they are supposed to be, but the angles are correct so the planes are perfect.

Suffice to say, there has been a whole lot of double checking before cutting on this job!