Twisted Top Plates Question

[Michael NY TF]

I am about 75 joints into my 10x14 square rule shed project. I have a question about my 6x6x13' long, continuous twisted plates (top plates?). One corner is "down" about 1/4" with the corner at the other end of the plate being "up" about the same.

The top and outer edges of the beam are the reference face and side and are at 90 degrees to each other. The post top tenons will be coming into the underside of the plate, and the rafters will be coming into birdsmouth housings in the top. I'm looking at several options for keeping the roof level and untwisted:

1. I could use snap line square rule and reference to level. This would cause one side of the housings to be shallower than the other, but wouldn't look bad. One end would have some part of the beam pushing the siding out but I could probably plane it out.
2. I could try to plane the twist out now to some degree. In that case do you plane down the reference side/face or the opposite faces? If the reference, are you worried about planing it out of a 90 degree angle?
3. I could not worry about it, reference from the edges, and try to pull it untwisted using strap or something at assembly.

Other than the questions above, curious what people here would do. A picture I used when trying to think about it:

[Roger Nair]

I, for example, plane the two square reference sides straight, flat and square to each other, using a 300mm electric hand held plane and winding sticks, flatten the first side.  I then make the adjacent side square and straight.  It's an eye ball process: sight, mark, plane, check and repeat as necessary.  I use framing squares for winding sticks, on a 8 inch timber, if the sticks coincide by 1/16" the actual surface is within 1 / 48th, so you can work close without striking lines or working from a grid on the ends of the timber.  You can trust your eye.

[routestep]

I would snap chalk lines. Depending on how your rafters are made, you might cut into the top of the plates, a little deeper on the one end and a bit shallower on the other.

[canopy]

Normally I would snap line square rule. But in this case since you want a flat side for the siding so it would be ideal to plane that face square. And since planing one side, may as well do the top as well and stick to square rule. Housing depths vary timber to timber and no one is going to take a tape measure and quantify whether both sides are the same so shouldn't be a deciding factor.

[witterbound]

Snap line.  I doubt you'll notice a 1/4 inch difference when putting on your sheathing/siding.

[Brad_bb]

1/2 inch in 13 feet is not insignificant.  Any chance you can use a new stick? Cut it and assemble the frame so it can dry in the frame.   After the twisted piece dries enough, mill or plane it square and use it for something else.  That's my recommendation. 

[ScottInCabot]

Do you happen to have a photo of the endgrain on the actual timber?

Wood stress is a wonderful thing....things move. 
What is the moisture constant of the piece you have, if known?



Scott in Cabot

[Michael NY TF]

Thanks everyone for the opinions. I planed the twist out using both electric and hand planes. Wasn't that time consuming, and worked out well. I could have also snapped lines, but thought planing might be easier than snapping when it comes time to lay out the angled cuts for the rafters in the top of the plates.

Scott - I don't have a pic of the end grain. This beam has been cut for about 6 months. With the mills around here, the three I know of anyway, you can't really specify things like boxed heart, free of heart, etc. You take what you get, at least when you're a small customer like me without repeat orders. Anyway, it has been interesting to see how pieces move, check, etc in relation to how they were cut.

If I do a larger project I'd order from someone who really catered to timber framers, even if it cost a bit more. I'm generally happy with the quality of the pine I got and didn't encounter too awful movement. I also let things sit for a while before cutting, so probably experienced some movement and shrinkage before cutting that others would get after it was up. After I'm done with this one, I'll rest awhile before my next project. Its cold outside! And by the way, I don't see how anyone can do just one frame. You have to do at least 2 in order to erase the memory of all the embarrassing mistakes and the first joints that took 2 hours to cut on your first one.