I wish I could take credit for the capital, knee brace, ridge connection detail, but my brother in arms Brad came up with that one out of the blue. I think it looks beautiful with the scarf sitting on top of it, and talk about a bomber connection. And you haven't seen it yet, but the eave wall also has a matching scarf joint (though smaller) and the relationship between the ridge scarf and the wall scarf makes for another layer of interest, I think
The only reason we even had the capital is because a couple of our posts were too short and so we needed to "stretch" them. We actually had parallel chord trusses in the original design, but, for a variety of reasons, we decided to forgo the bottom chord and go with knee braces.
I like the fix/choice, been there, it is nice to have other input info to such decisions, something my one man crew is missing.
Often times splice location pops it's head up and looks around. I wonder how this splice and block would look on a graph with stress and bending applied?
Let me look through the 80+ page engineering booklet and see if I can find the analysis of the scarf, though, if memory serves, he wasn't worried about it at all, especially since the ridge is so well supported.
+1 on having smart and creative guys around; we have quite the collaborative effort going on up here and it is exciting to be a part of.
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!
Thanks for taking the time to post something; it sure seems pretty quiet around here, you know?
Hahaha, questions like how many hours we have in each bastard valley are what I try hard to never think about. Suffice to say that, by the time we were done cutting them, I was completely over even looking at them. They sure look magnificent, though, I think.
Thanks for complimenting the joinery, my friend. As you can see, there was no margin for error with so many bearing points sitting on other timbers and with so many valleys zeroing out on one center line; any error in elevation would not only have been catastrophic, but would have remained hidden for the months before assembly when all of our ability to "catch up" a problem would have been gone because everything was cut already.
Yeah, we often clip our jack and purlin nosings, though, with the Fein tool making the cutting much easier, it is less necessary from an ease of fabrication standpoint. All of our jacks and purlins were scribed into their valleys, as opposed to square ruling, so it was actually easier to just leave the noses going to a point. I guess they are a bit more fragile during shipping, but the points completely bury anyway, so that wasn't a big concern. Plus, with leaving the noses long (and the housings a bit longer than scribed), we were left with a bit of lateral adjustment that we thought would be helpful, maybe, during the raising.
Next post will show the bastards being place in space, in the shop, for all of the scribing! And that was was no small task, let me assure you.
Not too much on this end over here Chuck. A restoration job on a historic structure right now, scarfing the bottoms of deteriorated verticals and rebuilding an octagonal roof, but no big stick stuff.
Yea its a little quiet, but at least we all have this cool thread to follow...
I'm going to have to look into this Fein tool you speak of..
Hey Mo, that sounds like an interesting job! I don't if it is something in the water these days, or what, but the last three projects I have been involved with features octagons as part of their design.
WTF? I see the damned things in my sleep...
If you weren't joking about the Fein tool, and I assume that you must be, then you need to go buy one of those things right now! You won't know what you did without it. And don't buy the cheap knockoff brands either; the Fein is so expensive because it is bullet proof and awesome.
HI Mike, nice to see you here! Yes, what you drew is exactly how we are cutting the jack rafters. Another nice thing about doing it this way is the cut across the rafters (3 1/2 x 8) is one slice with the Bigfoot. When you say undercutting the valleys, I assume you are referring to cutting in backing cuts, because we are for sure doing that, too.
Chuck, did you consider cutting blunting the tip of the jack, so that the downslope side of the housing is 90 degrees to the side of the Valley? That's common practice. The idea is that the jack will not act as a wedge. Imagine some thrust down the jack, and how it might want to pop the face off the valley. If you have the "red book", read the last paragraph on page 87, which explains it better than I can.
It's not difficult to cut these. On the Valley, it's easier to make a plumb cut than to undercut. And on the jack, once you've made the main cut like you already have, all you need to do is set the saw to 90, and set the base on the face you just created when you made the main cut, and nip off the corner.
I'm sure Mike will be along with a nifty picture illustrating this momentarily.
-- Clark Bremer Minneapolis Proud Member of the TFG
