Square rule seems to me to have a couple of drawbacks. I feel like seeing if anyone else sees these problems, sees through these problems, and/ or what they think or might do about it. First there are only two types of square rule that I know of. You can use the edge of your timber to square rule or you can use chalk lines to square rule.

When using the edge you come across the problem of timbers not being straight enough.
A tie beam that holds joists or a plate that is bowed could be an example. If the tie beam that accepts joists has a bow in it and you use the edge square rule you will have joists that don't fit. A little persuasion with trucker straps can be helpful. It seems you can do a little of this with bent pre-building, but what about timbers in the wall planes thereafter, or vice versa. I guess because of this people started using chalkline square rule.

Chalkline square rule is good because all of the reference lines meet up and you do not have the previously mentioned problem. The problem you have know is faces that do not meet up that frankly look ugly. For an example: You have a king-post with a collar. The collar is bowed in the level plane, so you snap chalklines for reference. You lay-out the pre determined dimension for the mortise to accept the king post off of the chalkline. Then after it is assembled you look up on your collar and see the endgrain of the kingpost shoulder sitting proud of the collar. In my opinion, this is no good.

Wasn’t’ square rule developed so you could come up with set instructions such as 2” to 2”, ½” Under Nominal, etc. and people could work and assemble with expedience (I.E. no mapping of joints involved). But how do you get around these problems without resorting to scribe rule, or mill rule? Is the only way around this very thorough timber designation and liberal culling? It seems you would have to pick each timber in an entire frame and designate its specific place beforehand, and then by the time you got to cut it, it moved.

Thanks for any input, Mo

Mo,

great questions. what is the best way to deal with bowed and crowned timber using the square rule, both from the edge and from the line.

Here is some of what we do.

Situation: bowed bent girt or tie beam with joists joining both sides
Dilemma: do you snap a line on the beam or try to straighten the timber?
fix: lay out the joist pockets from the edge and then use the joists (and perhaps a truck strap) to straighten the girt.

Situation: crowned bent girt or tie beam with joists coming in.
dilemma: hump in your floor.
fix: If it is too much crown, plane it back into tolerance.

situation: bowed wall girt or plate.
dilemma: nobody likes a crooked wall.
fix: plane it straight if it is out of tolerance and can't be replaced.

situation: bowed collar with king post joining it or similar situation.
dilemma: the faces of the timbers won't be flush if you are using snapline square rule.
fix: Best way to deal with it is to either plane the faces flush after assembly or lay the mortise and tenon out from the edge even when snapping lines to keep the faces flush. There is a certain amount you can fudge that before you mess up your shoulders.

You mention resorting to mill rule to avoid these problems, but you have to deal with crowned and bowed sticks that are planed, too. Maybe it's just us, but we rarely get any perfect pieces of wood.

I think that all of these solutions remind us that it is expensive in labor to build with crooked, twisted, or otherwise irregular wood. Some times that is the nature of the project, such as when using hewn timber or reclaimed timber.

I would love to hear how others deal with these issues.

gh

Good question and I would agree with posted response, I would like to point out that the question posed as a drawback to square rule is off base. The draw back is not the layout method. The draw back is the irregular timber. Square rule is a method for accurate and consistent lay out and joining of irregular sized and shaped timbers with predictable results. In this way it performs quite well. The concerns raised are aesthetics regarding mostly whether timbers meet as flush surfaces and such. These do not affect the ability of square rule to function as a layout system.

Good point, Michael. I completely agree.

When I use snaplines I relate the lines to what would be the reference face in edge square rule. before placing level lines on the ends of the timbers, I will split the difference in the twist or bow or whatever the timber is doing. In this way the surfaces will generally meet as well as they can. Surfaces that come out looking bad will be adjusted during fitting.
If you're dealing with wood, then you will always be using a bit of scribe technique to make it pretty.

So, if I have a 7" x 7" x 24' plate made out of hemlock which was planed, and it has a twist to it, should I level the points where the joinery will attach? By using winding sticks and planing these location true?

Gabel thanks for the dilemmas and solutions. That is what I was looking for.

Yes my question is off base. I guess I was under the line of thinking that the more irregular wood would naturally be square ruled as opposed to the more consistent wood that could be mill ruled. That is a whole different discussion. Anyhow even with the offbase question, I think the question is still there about how to deal with those issues.

Does anyone plane where gains would be to have a consistent slope to create a more gradual gain. For example a tie that has gains on the bottom at the posts. A taper?

I've got a nice collection of timbers out back that I'm pretty sure the client would have considered to be "a problem" had we had used them.

That's what we build our stuff out of.


Mo,

It's true you can use the square rule to join any two pieces of wood (even two logs), but really twisted and bowed sticks should be called what they are -- poor timber. And as such you should think long and hard about it's suitability. We have found that it is usually a good trade to pay more for better quality timber(not just the wood, but also the milling). That way we can spend the client's money on things they care about (or things you really want to do) rather than spending the labor joining bad wood and saying "Don't you think the scarf between those 2 really wonky sticks turned out nice and tight?" only to have them say (or think) "Why did they put those 2 wonky pieces in my dream home in the first place -- I thought I was getting better quality material."

That being said, sometimes you need to be able to deal with really irregular wood (natural shapes, reclaimed timbers, or just bad wood). My opinion is that scribing allows for greater flexibility in dealing with the sometimes unexpected consequences of joining 2 irregulars. Each intersection is truly "custom".

Square rule (and herein is a large measure of it's value) is more of a production method for dealing with irregularities in your timber -- with an accompanying decrease in joint specific control of timber surfaces without resorting to extensive mapping. That's why you just have to clean it up when it's together -- feather it in, plane it flush -- whatever looks best.



Once again, I think this is a great topic -- let's keep the ideas and opinions flying.

gh

This is a profoundly informative thread. To me this is one of the primary challenges of timber framing and I think Gabel has it right that using square rule as your main production method of laying out and cutting joints, but then perhaps during trial assembly or even at raising to use techniques from scribe rule to make the frame come together better and with more character as well. Hopefully one would have the time to spend on such custom fitting , as I believe it is exactly that character trait that we all admire old barn, mill , house frames, etc.. Gabel what do you mean by "feather it in"? Jim what are winding sticks? tb

tb:
I don't have a picture here that I can upload so I'll use this drawing.



In this drawing I have a 7x7x24 timber with two framing squares hanging on it.
One at each end.
Now if you got down low enough so that you could site the top edges of the framing squares the 24" leg horizontally it would show if the timber has any twist in it.
It will show because the square furthest away will not be "in line" with the one closest to you.

I did discuss this with one of my former teachers and he suggested that we use the center point and compare one end to the center first.
And if the end was off plane the end until it matched the center.
Then compare the other end to the center.
And then plane that end until they match.
This would hopefully take half the twist out of the timber on each end.

Hope this helps...