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...

if you have a collar beam joining a rafter pair and the collar beam is twisted, even if the shoulders are perfectly tight, the faces of the 3 timbers will not all be flush at every corner of the collar. So you plane off the high spots and feather it in -- blend it back into the unplaned area. make it look like you didn't plane off a high spot. hope that clears it up.

gabel

Thanks alot Jim and Gabel. That is really helpful. I think it is a great idea to use the center, to at least diminish the amount of error caused by a twisted timber. Do you use this technique with a crowned timber as well? thanks again tb

I apply a generous amount of common sense and rub it in well. Every thing mentioned in the above posts sounds great, I like trying new techniques to solve problems. I try not to be overly concerned with edges not coming into plane due to twisted timber,(use Jims method, or a level and a feather mark) as long as the joint is square the structure will stand square. I do understand the the reasoning behind having every thing neat and tidy, it's a personal opinion. I have never had a client complain "those two members aren't in plane", and I have had some fairly wanky stuff. When working with rough sawn material your 9"x9" isn't 9"x9" there are many options. One of my last resorts is to put it back on the mill and resaw. Voila' a perfect reference face. I know every shop dosen't have a small band mill but they are handy and worth looking into. Tim

I used mill rule when I was taught in my class. I suppose that's the easiest to teach a newbie. As has been said, few timbers are actually straight, thus the need for other layout methods. I am confident I understand square rule, but have yet to practice it(soon...). Precise measurements were stressed in my class to give nice tight fitting joints. It would seem that it would be more difficult to be so precise with measurments, given the width of chalk lines and having to judge the center of a chalk line. This leads to housing the joints according to what I have read. This is understandable, but I have one question... If you are putting a mortise in your second (tertiary) reference face, what technique do you use to measure the depth of your housing (the face) relative to the Chalk line on your Primary face? How do you hold the squares? It would seem kind of awkward to try and hold your framing square to your Primary reference face at a set distance from your Chalk line, and then hold your machniist square on the narrow tongue of the framing square measuring the depth. Am I incorrect in how to do this? I suppose I must clarify in that the housing is a full housing whereby you cannot just measure from the edge to the chalkline.

What is the best book for learning Scribe rule? Hey Brad!! How are you? I thought we learned square rule!! What is the difference between mill rule and square rule?

Carlos

Ok I just read the tread about scribe rule. Guess I found my answer...now on to build my Mcmansion. : )

Carlos

First of all you have to understand that the chalk line is not the standard line that comes in the chalk line tool when you buy it from the store. Usually most timber framers replace this fuzzy fat line with something that will produce a very fine true line. The replacement product is a braided Dacron, most commonly sold as a fishing line, (at least I think that's where you can get it).
Using this thin true line it's easier to hold the framing square to the chalk line....

Jim Rogers

Great info Jim. If you have any more info on recommended Chalk tool, the line etc, please let us know as I need to get one. Is everyone else doing as Jim described?

PS Jim, how's Thomas doing on my Chisels? Were you able to order the 3 sheaths I needed? Thanks.

Here is a line I've been using for a while, and I bought some fishing line like Jim says to replace the amazing but short lived line that comes with it. The thing I don't like about fishing line is that it is not stretchy enough. Fine for square timbers, but not round.

Mark, the line I should look for is braided Dacron? Cabela's seems to have it in all different weights, 12lb to 50lb test. What do you recommend?

We have some we can sell you if you can't find it. We had in the past 50 lb test and 100 lb test.
I've been chasing the supplier all day for your sheaths and he says they will ship soon.
I'll let you know when they are coming in....

Let have our milling done by people that know what is going on.

Thanks.

Fly fishing line and not the floating stuff, nor monofilment (ck spelling) braided Dacron sounds good. It streaches just right and leaves a nice fine line. Also most square rule is based of a reference face and is very precise and from my point of view easy to learn and apply, no need to use mill rule. That is mostly because I use only rough sawn stock. I think even with s4s timber I would still square rule, and that would be a breeze, no wany edges wow!

brad, what do you mean by a full housing? Maybe a 4x6 coming into a 8x8 that is centered and than housed? Tim

Thin lines are good, but it is not difficult to judge the center of a standard chalk line. Remember -- a carpenter's best tool is his eye -- and it is like any other tool. The more you work with it, the better you get with it. Sometimes we use too many crutches in our work and it only slows us down and lowers our skill level. Practice eyeballing things -- you will surprise yourself with the accuracy if you work at it. I'm not saying to put up you tape measure or framing square, but judging the center of 1/16" or 1/8" -- how far off are you really going to be, folks???

Brad -- what do you mean by a lack of precision in snap-line square rule leading to housing joints -- do you mean to hide sloppy work? Sloppy work is sloppy work -- the system is as accurate as the carpenter using it. It is not inherently imprecise.




yes, accurately checking the depth of blind housings on non-reference faces is not easy. There are many ways to do it.
the easiest is to put a straight edge across the timber at the housing and shim it on one side or the other until it measures the same distance from the bottom of the straight edge to the chalk lines on the 2 sides of the timber. Now your straight edge is parallel to the reference axis(or perpendicular depending on which axis you're talking about). Figure out how deep your housing should be from the straightedge and measure it with any tape, ruler, etc.

Will Truax and Glenn Dodge developed a nice tool for this application (the Regent), but the square and wedge work just fine.


For those interested in this subject, stay tuned to the next couple of issues of the Guild journal -- at some point soon, there's a new article on snap-line square rule coming out.


gabel

I forgot to mention that a lot of people are just bad at snapping lines and they end up with really fat, fuzzy lines. Changing the line probably won't help.

If this is your trouble, try 2 things. After you pull the line tight, hold the smart end away from the work and lightly pluck it to remove excess chalk. Now you shouldn't have so much chalk on the surface of the string that it spreads out on contact. Instead, the chalk "in" the string will be all that is laid down.

And number B. When actually snapping the line, most people snap it way too hard and the chalk scatters -- some goes off in the wind and the rest is scattered out making a faint, fat, fuzzy line. A really good carpenter once told me to drop the line. that's a pretty good way to think about it. Pick it up 8 or 10 inches and drop it. Some of the high performance line has a ton of stretch, so I'm not sure if these rules apply to them.

Around here, we have a saying when somebody snaps a bad line.

"It may be faint, but at least it's fat."

Gabel, I was assuming a big fat blurry chalk line. Jim and Marks comments about relining with the Braided Dacron would seem to help that. Your tips for snapping are also quite useful.

Bravo, Gabel! You would be surprised at how many folks snap the line to hard, leaving the chalk behind. Also don't drag the line around on the work surface before snaping, it gets confusing. Tim

If one is using chalklines on an irregular timber to define refence faces and edge, then doesnt that leave a portion of this timber outside of the finished building profile. For instance an exterior post that is layed out with its crown toward its side wall refence face . Or is it that one would plane down the timber that lies outside of the the chalklines in order to apply the enclosure for the frame? Or do you just deal with irregular surface as you apply the sheathing, exterior...? Maybe this is a stupid question? Maybe if you have pretty straight pieces ,this does not amount to much, but then why would you even need to use chalklines then. tb

I have discussed crown in a post before with several timber framers or timber framing instructors, and each can have their own method or placement of a crown in a post.
We mostly, here at my place, put a crown in a post so that the crown is in towards the center of the building. And let the vertical siding span the gap in the crown. Because if you put the crown out and then put on vertical siding the siding would bump out.
If you use horizontal siding and the crown is in you can shim out the boards to make the true.
If you place the crown out and use horizontal siding then you have the bump out again.
So in that case you probably should plane off the crown if you're going to have the crown out.
The chalk line is just a reference line for aligning the joinery to all one plane. It doesn't mean it's the outside of the building.
Some people use the center line of the timber as a reference line.

Jim Rogers

Thanks Jim. I guess I was confused.( on a post for example) I thought you would lay out the chalkline as close to the edge as you can,(the last straight line that you could snap within the timber) , of your timber exterior reference face, and this would become the last straight in the timber and also the building. I thought to place the crown out ,as I thought its natural curvature towards the the interior of the frame would help fight the rafter thrust more , but maybe this is incorrect as well? It definitely makes more sense like you said to place the crown in when considering enclosure. thanks tb

Although I haven't personally used chalk lines a lot. I believe the chalk line is laid out on a timber to some standard dimension such as 1" or more commonly 2" off the edge, so that the measurements can be easily figured. But someone who has had more experience with this should post the reasons why.

I was reading a TF book the other night about square rule and it said to put the chalk lines at 1.5 which is what the narrow side of the framing square width is. When reading that, I wondered if they meant that a tennon would have to stay inside the talk lines instead of going to the edge of the timber on each side. I'm not sure if that is what was meant, but I don't think so. I think they just want you to use the lines as measuring references to keep things square to those lines. If the distance from the chalk lines to the edges of the timber were not equal on each side, I think then that your tennon would not go to the edge, but rather would be centered relative to your inner timber(chalk lines) and the specified width of the mortise. Correct?

Which book are you reading?

Unless I'm mistaken the chalk line is just a reference line. It doesn't mean that this is the side of the tenon unless the layout is 1 1/2" off the true outside corner and then the mortise is 1 1/2" wide.
If the layout was 2" x 2" then you'd layout the mortise 1/2" off this 1 1/2" chalk line every where long this timber.
Does that make sense?

You are confirming my understanding Jim. It didn't specifically say those things. It's what they don't say that leaves me with questions. And the book won't answer my questions no matter how many times I ask
I'll have to get book name from home. It's one of the common ones. (I bought about 6 books based off the recommendations of Thomas Massie's blog).

Jim, that is correct about the chalk line being the reference line. If you have do use 1.5" of the reference corner and you have 3" braces that are 1.5/1.5 you could then just use the chalkline for one side of the mortise.

I did a little sketchup drawing but can't access my photosite. When that is up i'll post it.

Here is another problem that I am thinking about.

1. If you have a post and you decide to put the bow in. When you lay out your wall bracing on the post with this method your brace will sit proud of the post on the outside however much the post bows in. Then when you lay-out your bent brace connecting with the same post on the adjacent side, you would have an extra deep housing.

2. If you take the same post and put the bow out. The wall brace would sit shy of the outside of the post in the plumb plane. And then you might have to map a special bent brace to reach that same post because the bow is out.

Any thoughts?

mo

Mo, If I understand you correctly, you are thinking that the brace will be pushed further to the inside of the frame by the bow? That would only be true if you were using mill rule and basically measuring the depth of the brace mortise from the surface of the post timber that the brace rests against. With square rule as I currently understand it, you would measure the depth of the mortise from the reference chalk line(s), which is not bowed. You are thereby placing the brace into the timber relative to the "perfect" inner timber. You've created this perfect timber with your chalk lines, which you are measuring from, and you house your brace so that it's face will rest against a correctly positioned face(not the outer bowed face of the timber) which you create relative the "perfect" timber. It's all beginning to make sense to me now. Now I just have to get to practicing it! I plan to prep reclaim timbers in Feb and try to get a design on paper by the end of Feb so I can start layout in March.

I think Brad has a grasp of it now....
And mo you may have some points about the brace also.
But if the post bows in and you layout correctly you should have a deep housing.
If the braces is too long, it will show up when you do a fit up test with all the pieces of that bent. At that time you could trim the long brace back to correct it and make it work.
If the post bows out and the brace is too short then you'll have to cut another longer brace, possibly mapping as you have mentioned.
I would think it would be easier to trim a little off something that's too long then to have to replace the entire piece because it's too short....

Jim Rogers

If the brace is made to "print", and you've layed out the mortise/housing correctly using square rule, the brace SHOULD fit properly without any changes. As far as the brace is concerned, it should not know the difference if it's in a bowed rough sawn square rule post or an S4S mill rule post. The housing or respective mating face is in the same position in space in either situation.

Brad, As far as I am concerned you never lay-out from the inside face the depth of the housing for the brace. I can think of the only time when someone would do that and that is when a inner post has braces that meet on both sides. I personally would create a centerline down the post to lay these out. Even in Mill Rule the reference faces are used as references.

Now back to the curved post. Are you sure about not having to do anything to a brace to make it fit?

Here is a photo of square rule with straight sticks.


Now the problem with the bowed post.




In this situation if you were to use the patterned brace the nosing would be hanging in mid-air and there would be no housing on the post, in short too short. (Example: working 1/2" under nominal)

The only remedy I can see to fix this would be arranging your post with the bow in creating a deeper housing, or picking a different post that is straight damnit, or moving your brace in on your tie 1" towards the post and then work 5" off of your chalkline.

The idea of snaplines to me is access the simple line at the center of the timber. I place plumb and level lines on the ends of the timber. On an 8x8 timber for example the lines will be 4" from the reference faces on each end, on a 10x10 they would be 5".... The lines on each end will be level to each other.
Then the lines represent extensions of the simple line at the center of the timber.
To lay out a mortise or a tenon, I would use the snapline as the inside of the mortise/tenon on an exterior frame, or the center of the mortise/tenon on an interior frame.
Here is a sketchup model that uses snaplines, with centered m&t, as in an interior frame.

Cull the post, put the bow to the inside, or move the brace -- those are your options, mo.

This happens in other circumstances -- crowned rafters with a collar joining. Or a bowed floor beam -now your joist only has a 1/2" bearing because you laid your joist pocket depths out from a chalk line -- you got to make your joist longer and get a deep enough housing. Or anywhere 2 sticks join each other and one bows away from the other so much it is outside the lines of it's "perfect timber".

The bottom line is that working with wood this curvy is a pain. You can't get all the efficiencies of square rule going, because you end up with an exception to each rule. "Was this the girt that is only 7" tall?" "Which one was it that had a 3/4" sweep, so we have to move the . . . ?" The drawings end up covered in little notes to remind you what you did here or there, so you can remember to shift this or change that length. You end up square-mapping it and it's a real pain. But it can work.

It's a really strong argument for using good wood.


Then there's always what a guy I worked with once told me. "You'd be amazed how much you can bend wood"

and sometimes, that's the approach that makes sense.

Good points about all of those notes becoming clustered.
Maybe scribing is the way to go?

You guy sound like Al Gore and global warming, in that he stretched he truth to make a point. Ifits that bad cut it in half and us it elsewhere, re saw it, hew it straight, or something. But lets not make this more dificult than it needs to be. Square rule is simple. If your timbers are that wanky, scribe, or have them resawn. With that all said, If I have to snap lines for lay out, my line represents one side of the mortice, no need to recalculate off a center line or some other number. You can still plumb and level on the ends with lines that are not centered. I also only snap lines I need, if no joints on the other three sides, no lines. Tim

Many ways to skin a cat...

Jim, the book I was looking at was Jack Sobon's book "Building a Timberframed House, copyright 1994. I was reading the short section on layout for Hewn timbers. There he uses 1.5 inches, the width of the narrow tongue of the square, as the approcimate inset distance for the snap lines.
Brad

oh well, so much for thinking

by the way "narrow tongue" is the department of the redundancy department. "tongue or blade" and body. Just some basics. OK thats all from me on that.

brad, in that book the post are hard wood, Jack is using 1-1/2" mortises due to the fact that it is much harder to bore 2" holes in hardwood, if the post were softwood you would of seen a line 2" off the ref. face. He would not of snapped a line 1-1/2" off than calculated the extra 1/2" to the 2" mortise. On page 78 it clearly says "edge of mortise/tenon" with a arrow pointing to the line. Also notice that every thing is housed to 7-1/2" on a 8" timber, forming the inside face ready to receive the incoming member. That is only an example, on the actual frame he used a layout tool, based on the hard edge of the timber, no snap lines, see page 85 top left photo. Tim

Timbbeal,
So what are you saying? If you didn't have the exact example he did, you would always snap your line exactly to the edge of a mortise/tennon? Let's say your reference face is not uniform. What do you base the measurements of the end points of your chalk line on? Do you stretch a chalk line to hit the highest points of your reference face and measure from there?
What if you have multiple mortises in a face at different locations like a beam intersecting in the middle and a brace whos mortise is not centered? Just trying to clarify and get a better understanding...I'm really surprised that there doesn't seem to be a nice layout video out there that shows all three techniques and their nuances. That would be a good thing for the guild to sell online. I've heard that there have been demos at conferences. Surprised no one taped them for a video. There could be quite a number of demos by different Timber framers.

Brad, when a timber frame designer make a set of decisions about a frame's design they are generally called "General frame rules".
These general frame rules are such things as 1)all joints are reduced to the next 1/2" down in size. 2)all joints are 2" off layout face and then 2" thick. 3) all bents are laid out from the west side except the east most bent. 4) braces are framed to 4" thick.
What this means (#1) is that all joints are reduced to a common size so that irregardless of the size of the rough sawn timber the joint is sized to one common size. So the tenon on the end of a 8x10 tie beam is sized to 9 1/2" and and mortise is sized to 9 1/2" and the housing where this tie beam enters a post is sized to 9 1/2".
What this means (#2) is that all joints are laid out from one of the reference faces on both the tie beam and the post, using the above example again. So even though the tie beam is 8x10 and the post is 8x8 the tenon and it's mortise is 2" off the layout face and then 2" thick. Also, the brace pocket in the tie beam and the post are also laid out to the same spacing. This keeps everything lined up and easy to layout and cut. This the value of square rule framing.
What this means (#3) is that irregardless to which way the frame will sit on the lot when it's raised, the designer has placed a compass north arrow on the plan and it is used to understand which way is east and which way is west. And the interior bents are laid out to this rule. This again makes it easy to layout joints and cut them.
What this means (#4) is that if you have a rule like #2 and you have 4x6 braces the tenon will be 2" off the layout face and then 2" thick. But the brace is 4" thick so what happens when the brace stock has shrunk while waiting to be cut? You can't move the tenon off the 2" offset. You can't make the tenon 2" thick as the stock has shrunk. So, what do you do?
You don't order 4" stock for braces; you order 4 1/8" stock or thicker. Then you have enough wood to layout your tenon 2" x 2" and then you shave the back side of the brace stock so that the tenon ends up 2" thick, using a hand plane.

So in your frame your chalk line will show you the 2" offset and all mortises should be on the line, if that's your "general frame rule".

Now in Jack's house the posts were oak, and therefor stronger so he used a different rule that the tenons on the oak posts could be 1 1/2" off the layout face and 1 1/2" wide. And as I have just reviewed his book and frame design again, it appears that most of the joints in that house frame are 1 1/2" x 1 1/2", with the exception of the scarf joint tenons. So that frame will have some general frame rules and some exceptions to those rules.

Standard timber framing rules for sizing tenons are that the tenon should be 1/4 the thickness of the timber. So an 8x10 tie beam should have a 2" thick tenon. And another standard timber framing rule is that the peg diameter should be 1/2 the tenon thickness. Now each frame has to be individually evaluated by a timber framing engineer to make sure the joints won't fail, but these are some standard rules.

Jim Rogers

That makes perfect sense Jim.
I would like to make a couple of comments on set up, and you guys please tell me if I am off or on.
Say I'm preparing to layout a post. I decide to put the crown to the inside of the building. I stretch the chalk line along the primary reference face let's say two inches from the edge that meets the secondary reference face. If there are any high spots in the middle pushing on the chalk line, plane those down. I could also optionally plane down the ends to try to take some of the concave bow out of the primary reference face, if I want to, if it's excessive. When setting up this first chalk line, I measure 2 inches from the edge at each end of the timber. There is nothing, however, to say that the secondary reference face or edge doesn't have crown or wankyness of it's own. Therefore, before snapping my primary face chalk line, I must make sure that my chalk line is 2 inches from the highest point of the secondary face edge. I may want to stretch a chalk line along the secondary face and look for high spots and plane that face closer to being straight and level(square with primary face). It is only then that I may snap my first chalk line. Is this normal or typical? I understand that you may elect not to plane or modify the timber at all, such as in the case of a hewn timber. In that case, you may decide to measure as best you can and determine the location of the first chalk line. I then assume that you will determine the secondary face chalk line endpoints by both using your square on the end of the timber and measuring 2 inches as best you can from the reference face. Comments?
Brad

A while ago I discussed this with a friend and former timber framing teacher of mine. He said that you can plane down the ends some, but the limit is the amount you're going to reduce the timber to make a joint. So for example if your general frame rule is 1/2" under the size of the timber then 1/2" is all you can plane off the ends to try and straighten it out.
If you plane off more then you're going to be under size on your joint on the ends.

I thought at the time that idea made sense to me....

Jim Rogers

So I was looking for some commentary on the method I described in my last post... Am I on track? Have I got it down? Please comment.
Incidentally, I find it very surprising that of all the books I've got now, none of them seem to really describe detailed step by step approach to square rule or scribe rule.
It's like a friend of mine who wanted to learn a new CAD program. He got book after book, but they never bring it down the reader's level. I ended up teaching my friend, going step by step and pointing out all the little details and tips that the books never address. The little questions that the readers have that are never addressed. I basically taught it in lay man's terms as if I were the student. So many of these authors have difficulty putting themselves in the student's shoes and inadvertently gloss over details they never give a second thought to.

Brad, you're on track. Definitely. Get in there and do it, then send all your detail questions to the forum.
( -:
It's not easy to write about layout with words... I've tried to produce a number of handouts for my classes, and often feel what I've written is inadequate.

bradbb, Sobons book is quite thorough, and as Mark mentioned, it is tricky to put into words. You could take a class in square rule. As in a former post "many ways to skin a cat", maybe to many.

I have some questions for you. Is this your first project? Other than your experience at Fox Maple have you done any framing on your own? I also spent a week at Fox Maple, 11 years ago. I am assuming you are going to use the timbers you talk about in your blog. There for, the questions on lay out of rough stock. While at F. M. you were taught mill rule, which doesn't work with the stock you have collected. So, what to do? Take another work shop. Have the timber resawn. Do as Dr. Mark suggests. Or maybe all three. Well, I could go on but I have a scrub plane to sharpen, by the way do you have a scrub plane, they work nice for taking down those high spots. Lie-Nielsen makes a nice one. One more thing, you may have to eaze off the anal-retentiveness in some areas when working with these rough timbers, but use it when needed, that is the tricky part. Tim

Yes this will be my first project (my new workshop) since taking the class at Foxmaple, Other than a set of oak bunkbeds I built using the techniques from the class and my chisels. All chiseled mortice and tennons and mill rule on white oak 3X2 stock. That was before I bought my unisaw.
Yes we only learned mill rule at the Foxmaple course. Actually, over the last 6 months I have been learning all of the things we didn't get to touch on at the course. I realize that in only one week, Foxmaple crammed in as much information and hands on as I could handle at one time, hence the name "Introductory course". It was all we could do to learn what was presented that week. It was a solid foundation for continued learning.
My plan is to use square rule where possible. I will be having some of my reclaim resawn to get to the dimensions I need. I'm thinking I mentioned my retentiveness somewhere that you picked up on. I now like to say that it's a pursuit of perfection. It'll never be perfect, but you can pursue it.
No I don't have any hand planes yet. I've got my chisels though for tennons.

I think pursuit of perfection a much better description, one which everyone should follow. Check out the definition, it's ugly. One of the most retained and used tid bits of info I gained at Fox Maple was math, and to trust the math. That is if you can find all the triangles, leave one out and your....left with a redo. .7071 and the companions are used very much. Other people keep coming up with these construction calulators, which are like sugar, but I like to know where the numbers are coming from. How about a nice slick, I use my slick everywhere, hardly touch a chisel. Even with resawn stock mill rule laggs, Square rule, rules. Tim

Good observations all. We have a pretty good sawyer at Heartwood, and once you find one don't lose 'em. In a whole frame we will rarely have a pine timber that is more than 3/16" out of wind or bowed. That can usually be pulled out during assembly on long timbers. If we find one over that we will use it somewhere it won't matter (such an interior rafter that is bowed) and/or use snap-line instead of edge rule; if twisted we'll split the difference like Mark recommends. We often are leaving the timbers rough, so planing's not an option unless it's on an outside hidden face or top. Scribing and mapping are other options if it's really bad and just a few pieces. Last resort is to get rid of the piece, and maybe the sawyer. One thing to remember is that when square rule was developed aesthetics may not have been as important since mostly barns were timber framed, or houses where the frame would be covered or hidden in the attic.

Anyone have a copy of this spiral bound book by Jack Sobon???


The Scribe Rule or the Square Rule: Traditional Timber Frame Layout Systems by Jack A. Sobon (Spiral-bound - 1994)

Currently unavailable


I found it on Amazon but it is not available.

Carlos

Carlos, I have a copy. We rebuild a house frame here in down east Maine where they used the 2' scribe rule method simular to the method mentioned in the book. Tim

Tim

Is it a good book? How many pages? Would it be an infringement on copy right laws to scan it and recieve a "present"? Or would you like to part with it?

Carlos

I only have the one and can't part with it. Have you inquired with Summer Beam Books, via the guild office. I am unsure of how to contact them. They are at the guild conferences. There should be a way to get a "legal" copy. What is your interest in scribe and square rule? Tim

Check with summer beam books for sure. Char and Bill live near me and I've been over to see their collection, very impressive. She has a lot of out of print books as well. www.summerbeambooks.com

I'm just trying to learn as much as I can about this. I was on the course with Brad (brad_bb)where we learned Mill Rule. I've got some other books on order but this one looks good. Thanks for the link I will definately contact them.

Carlos

I was just rereading this thread tonight to see if I finally understand....

So to simplify .... could it be said that square rule and mill rule are essentially the same the difference being...

In square rule you run a chalk line first (preferably on an edge of a mortise or tennon)...and then you work from the chalk line instead of a milled edge

If this is so... in mill rule when we score a line we have a nice solid edge to hold the square... how do you go about scoring a line in square rule.... besides carefully??

Carlos

Carlos, if scoring is the biggest of the problems then so be it. I personally don't see the need to score. Why do you score?

p.s. check out the mill rule vs. square rule thread

Gain, Gain, Gain, with the ole chalkline rule.

Mo

Scoring just adds another level of precision. It is a technique used by cabinet makers. I'm guessing you do your layout with a pencil and cut to the line with a saw?? I was taught to score, cut off the line and then pare to the line with a chisel.

So do you agree with my statements about square rule??

Carlos

Carlos,

Sorry I was editing while you were posting.

I can see your point with scoring. But to me it seems a bit much.
Paring end grain with a chisel in my honest opinion is a %^&$% and seems to let ones sawing abilities not matter. They should in my opinion. Take half the line and be done with it.

As far as square rule vs. mill rule difference. As i see it you work from reference face to a set dimension on both, but in square rule you are probably left with more wood to cut out for housings to meet the "perfect" timber. That means that only structural housings in mill rule would be present but in square rule you have those housings for everything. Like braces. Braces don't need housings to brace do they? The bearing point of the tenon carries that right? Anyone?

Peace, mo

Carlos, score if you want. I gave up scoring after about a year, but not completely. If I am using a chain saw to make a cut, I score. Most every thing else is half the line hand saw or skill saw.

I love the housings left in square rule, even the brace. It has to be better. You end up with the whole section of the brace as a bearing point, most likely over done but nothing wrong with that.

I would like to reiterate, square rule doesn't always need chalk lines, some times but mostly not. It seems, through this whole thread, lines are attached to square rule, lines are an exception. Tim

Another thing to remember is that the lines can get blurred between mill rule, square rule and mapping.

For example, we are currently working on our fourth truckload of band sawn cypress for a project. 80% of the sticks are 1/8" over dimension and the rest are within 1/16 of that. And they are dead square. It is very well-sawn. It would be absurd to reduce an 8-1/8 x 8-1/8 to 7-1/2 x 7-1/2. We either make the housings/mortises/etc 8 1/8 or we make them all 8 and reduce the tenoned members to 8". Is this mill rule? mapping? square rule? I don't really care. It's all the same. If the stock is consistent you don't have to be so heavy handed in your gains and reductions and the visual impact of "square rule" becomes minimal, but you are still laying everything out the same way. Braces and timbers that need bearing are housed a set distance of f the reference edge (or line) that will give us the bearing we need.

The one underlying principal in all of the above methods is that all timbers are laid out from a reference corner or if it is a crooked or twisted or hewn stick, it gets chalk lines that represent a reference plane offset a certain distance from the reference corner.

As Tim mentioned, a lot of this thread is talking about a very specific circumstance -- when you are working with very twisted and crooked and dimensionally variable timber. Making a twisted and crooked 8 5/16 x 10 3/16 join a twisted and crooked 7 7/8 x 8 1/16 and have it look decent. We run into it occasionally, but usually the timber is better than that.

I think Gabel's got a handle on the difference between mill and square. In Mill, you can trust that the dimensions of the timbers will be close enough to their expected values that you can cut your mortises and housings to those dimensions. You don't have to reduce everything to the next smallest increment to account for significant variations in dimension. If you find an occasional deviation from what you expect, then make note of it and make the necessary adjustment on the mating timber (mapping). Regarding the reference face, if the outside face of the timber is too twisted or bowed to serve as the reference, then maybe that piece should be set aside as a "spare"?

And I always score. Leaves a cleaner saw cut, and there's none of the ambiguity of a fat pencil line. Just doesn't take much time if it's part of your routine. But the saw is accurate enough that we rarely need to pare the end grain back to the line. CB.

I understood everything except this comment by Tim. If you aren't using a chalkline, Are you then using the reference face and therefore reverting to mill rule? Please explain further so I can understand what you mean. How are you doing square rule if not using chalk lines?

brad,

Do you have either of Jack Sobon's books. Both of those present square rule layout from the edge very well.

The square rule originally used chalk lines because it was originally used on hewn timber. the edges of hewn timber have lots of dips and swells, as well as fat spots and out of square areas. All of which make applying a square to themis too irregular to accurately place a square on.

As sawn timber became more accurate, the need for reference lines went away. If the timber is straight and regular, why snap a straight line? It's a wasted step if the edge is true. For a lot of sawn stock, this is the case. The edges were pretty straight, but the dimensions varied enough to warrant reductions and gains at the joints.

The reason this topic is talking about snap lines so much is because the original poster was asking about how to deal with extreme situations.

Understood. So if the face of the timber varies by say 1/16th, or 1/8, or 1/4 inch along it's length, would you then need to revert to chalk lines? Would you have to asses each timber one by one by pulling a string or the chalk line along it to assess how planer it is in the areas where joinery will be cut? How much out of square would you accept(from primary to secondary reference face) before reverting to chalk lines?

I've seen lots of hewn barn timbers that have square rule layout and no chalklines, in fact I have rarely seen chalklines in barn construction around here. They must have used the square like a transit I spose, sighting down along the beam to find the edge.

Mark,

Could be. I like the idea of a transit.

Check out this description of square rule from a 19th century carpenter.

Light and Heavy Timber Framing Made Easy by Fred T Hodgson

When framing to lines, this is more or less the method we use.

By the way, I saved that entire book as a pdf, took it to a printer, and had it printed and spiral bound for about 35 bucks. It's public domain, so copyright laws don't apply. And it's a great read.

Here I go out on a limb. I am most sure square rule was developed for sawn material. It was part of the transion to speed up the framing process.

As for Mo's first post and his question of the downside of square rule, Gable is right, Mo example is a extreme one. 98% of my work is square rule all off an edge, no snap lines. Some times they are nice and square other times out of square by up to a 1/4". You use the aris, the true corner of the ideal timber. I hardly ever see twisted or bowed stock which is unusable. Most of my stock is soft wood and reasonablely fresh. If it was to sit around for ten years and it was hard wood I would have issues. The old frames were more likly to have been cut green and more true. I will spend some time looking at Gable's last post with the Light and Heavy...... link, it sounds interesting. Tim

It is interesting. The term "boxing" for square rule is a new term to me. I also liked the stepped square, sort of like the Big Al square, but with a bigger fence. And a way to reduce "blunders". And much more. Tim

Tim,

The earliest known square rule building is right around 1800. The transition really took off just after the War of 1812 and was fairly complete by 1825. In most places, that predates the widespread use of sawn timbers.

Maybe Will T. will chime in -- he has studied the "Great Transition".

That book looks cool. Where did you get the pdf, Gabel? Right off the site you linked to? CB.

Gable, since my first visit to this fourm I have learned much. I am still learning. Some of my comments may be a bit off that is for sure. In some ways I am just thinking aloud, with a base of common sense.

In the span of 25-50 years of the development of square rule, with the use of snap lines, things changed rapidly. That span of time is only half the life of a person, not long at all. Most people saw the changes and moved along with them and adding to them. I think this works in with the "Great Transition". I hear there is work in print on that, as well as the artical on snap line square rule coming our way via Timber Framing.

The town of Machias, where I grew up has a historical building cared for by the Daughters of the American Revolution. It is a dated building via specific records. It was built in 1770, the majority of the timber is sawn with a few hewn pieces. It is not square rule. The town was settled in 1763, when the French was driven out. The French settlement was not much, no development, more of just a presence. The saw mill was the first first priority. There was a huge presence of saw mills up and down the coast. Powered by rivers as well as the tide. lots of the mills were just temporary, and moved from tide pond to tide pond as the timber was cut and the land exposed. This is all within the dates we are talking about. So sawn stock was avaliable to aid in the development of square rule. In my limited literature I find no specific mention of only hewn timber, but I do see sawn and hewn used together, suggesting it was used on both and in the long run sawn timber became the predominant material allowing the snap lines to be lost as well.

Here is the odd thing. Most of the old farm buildings I see have a mix of sawn and hewn stock and almost all are scribed. The exception is the town buildings Hall and Churches, these are square ruled.

By the way, in the War of 1812, Machias and the surrounding area was taken over by the British, becoming British territory.

I would like to hear more on SLSR and it's history. Tim

Ok, so I have to own up to something today!! I went out to buy braided fishing line for my chalk line but didn't fully read the posts!! I bought 15 lb test!! Let's just say it dosen't work so well!! Line is so thin is comes out without chalk on it!! Whoops!! I guess I gotta go fishing now!!

Carlos

I bought the chalk line from Lee Valley and it seems to have a pretty thin line already. I will compare it next time I'm in the fishing store (Bass Pro Shops near me).

I primarily use square rule, and I only snap lines on timbers that have a pretty good bow to them. Otherwise everything is laid out off the reference face with Big Al. If there is no square reference face then I first swear at the sawyer, then use a framing square to make an imaginary reference edge.

The other Brad: to me, mill rule means no reductions on tenoned members, and typically no (non-structural) housings either. If you don't want to reduce your tenons to a common dimension, you can scribe everything, map them (measure the height/width of every piece, and map them to each joint), or use mill rule, which assumes that every piece that you ordered is exactly as you ordered it. If you're mill ruling a 4x5 girt to a post, then you assume or know that that girt mortise is exactly "5 or 4.75" or whatever.

I like Gabel's point about blurring the lines too.

Tim, is there any evidence of French scribe in your area of Maine? French marriage marks or framing sytles?

Brad

Brad, good question. First, I am sure 2' scribe rule is present.
2nd, I have seen four bent frames laid out with ref. faces toward each other/threshing floor, no 2' scribe marks. Am I correct in saying these are not Fench framing styles? What do French marriage marks look like? I would find it very interesting to discover a French presence in Down East Maine. I would be greatfull for any help in determining such a presence. Tim

I haven't totally figured out thesquare rule thing yet, but on the forum is seems like we've come in a circle. As far as I can tell square rule is the same as mill rule with housings and chalk lines instead of straight edged timbers. I just haven't figured out how you make sure the bottom of the housing is perfect.

For instance lets say that you want a brace centered on a post with a half inch deep housing. Let's say the post is 8x8 rough sawn stock. The tennon is 4 inches, the mortise you will go deeper so the tennon dosen't bottom out. The problem is the side of the brace end with no tennon is supposed to rest flush up against the inside of the housing. The only way I can think of getting a flat surface is by routing it out, which means that your original face would have to be your reference making the housing redundant...

do you follow me??... I'm not sure you should!!

Carlos

So I figure a picture is worth a thousand words!! Here is my housed brace mortise. The 2 bearing surfaces would be the red and the black. It is the red surface that I'm wondering about in the above post.

Carlos, check out page 5, Jim's post #14129.

There are always exceptions to most rules. Here is one. A King post that is flared, wider at the top than the bottom, 11" top - 8" bottom. Now, you have a 6" ridge beam coming into the top of the King, with a brace flush with the ref. face of the ridge. Where the brace lands on the king you will have a mortice like the one you posted. This is where you could use a snap line down the center of the fanned King and place the brace accordingly. To gain the red surface, assuming this is the non ref. face, the more tricky side, no, lets just call it the reference side for simplicity and you are housing it to 1" deep. Bore to 1" deep a series of holes and clean up, or use the router and clean up.

timberwrestler, how about those French marriage marks? Tim

Tim,

Here's some Frenchy style marks...

They look relatively similar to British style marks (I think) until you get to 6,7,8, and 9.
I'm no expert on French framing styles, but I believe that all interior secondary framing pieces (braces, girts, etc.) would be centered. There would be a level mark on every piece, and posts would need some kind of 2' mark (because they are in 2 scribing assemblies), but I don't know where they traditionally fall on the post. There would be no English tying joints or jowled posts. The French also mark their cuts differently using 'x's to mark where not to cut, and 'o's to mark the waste. Maybe some of the Timber Tour de France tourists, or Mo could add something to this.

and Carlos,
I basically never snap lines on square rule (in contrast to Will), as long as the reference edge is straight. And I could be wrong here, but there are no centered mortises in traditional square rule. Cutting a fully housed mortise on a non-reference face on an out of square timber is pretty damn hard. You could make a router jig referenced off the reference face, use a whole bunch of squares to check everything, find a square timber, or just scribe the braces.

Timberwrestler, is right about where you would place a brace pocket in a rough sawn timber frame, and that is on a timber's edge.

Sometime ago, I wanted to be able to do a centered brace pocket on a rough sawn frame and in doing this you have to make sure your pocket is the correct depth.
And this would be measured from the reference face, which would be the opposite side of the timber.
So, I invented a tool and had a machine shop near me make one up. And I have to admit at a great expense.
But this was a prototype:



It is two framing squares bolted together with a slider that holds a combination square metal ruler.

As you have heard of the Big Al layout tool, well this is a Big Jim's double combo.....

And here is how it would be used:



And a closeup:



Basically it would let you measure around a corner and then in.

I was hoping to find a machine shop that could produce these slider attachments and start selling them to timber framers who want to be able to use their combination square ruler with their framing square; without having to use three or more hands.

I have a machinist friend who is suppose to be getting me a price for making up say 10 of these to have on hand and sell.

If you'd like to order one, please let me know and I'll put a fire under his butt and see what's going on. I've been waiting more than a month for the price quote.

Jim Rogers

Jim, here is some matches,$$$$$$$$$. I am always a sucker for a new tool. I would give it a try, if it's not majorly over priced like that land cruser mentioned elsewhere.

timberwrestler, thank you. I have not seen anything like most of those marks. As you mentioned they are simular up to, well, around IIII (4), than the V is upside down and It doesn't pick up again till 10-14 in matching the English numbers, and I am not going beyond that. I have seen them in other literature, just could't place it, but not on timbers. I will keep an eye out. The lower ones look like stick figures? In the book reprint mentioned by Gable, that had some simular marks for keeping track of what was being cut and what was saved. It's interesting that O was the waste. How do we know that, if it was cut out? The X is present on many timbers. That is something I don't do but have often thought I should pick it up. I just thought the O may represent the bore hole, I do that, at times, make silly o's where the mortice is. Most likely it has nothing to do with it. How about eveyone else. Do you but the X at the ends of the mortice? Sorry I may be wondering from the snap line topic. Tim

Hi Tim,

From what book did you extract the French piece numbering tables ?

Regards

Ken Hume

Hi Ken, the print of the French marking system was that timberwrestler, Brad's. Maybe he will share that source.

I did see some German marking system in Timber Framing. I am happy to continue to type under this thread, snap lines, for this is somewhat still on a laylout topic. Or does this need a new start? I have always used 2" and 1-1/2" chisel marks North and South. With the bents labled 1-the # of bents, using the modified Roman numberals specificaly #4 as IIII not IV. I see the French system is like that as well but they also put marks within the inverted V. I scribble with lumber crayon as well during the inital lay out, blue-North and red-South. On some of the old frames I have seen they used red crayons and the penmanship was very neet, unlike my messy scribbles, I bet they practiced in school more than I. The chisel marks are the last thing I do to say I am done with these sticks and I feel they are more permanant. Tim

Hi Tim,

The whole subject of marking finished timbers is one that could form the subject of a research dissertation. Please keep in mind that marks can also act as timelines i.e. it is both possible and easy to mark a timber with a race knife whilst it is still green but not when dry and hard. So when dry i.e. as when timbers are reused then marks are more likely to be made using a chisel and mallet so it can become easier to identify what is and what is not contemporary with the original build of a frame.

I recently came across a 2001 "Libri Rari" reprint book of "Duetsche Holzbaukunst" by Carl Schaffer (ISBN 3-88746-432-X) originally published in 1939 which explains the numbering system for multi platform fachwerk frames i.e. where numbering elements regarding height, position and aspect within a frame are incorprated into the numbering system.

Regards

Ken Hume

Regards

Ken Hume

Ken, a dissertation does sound lengthy. This is all great stuff. I will continue to keep a open mind and a watchfull eye for such subtle details. I have not used a race knife, I wonder how dry a timber has to be before it is to difficult to mark with a race knife? I am seeing older frames with chisel marks and they are original markings. I see alot of 1" and 2" chisel marks. These systems are very simple as are the frames. Most of the boarding has a counting system marked via race knife, from the milling operation.

I am continuing to read on my local history and life here is the later 1700's and early 1800's was a difficulte existance. This area was not much for agriculture, mostly timber and fishing, even hay was imported, in some locations, for the working cattle. So, great barns are few. The sea captains had great houses.

As a side, what is the beginning date of balloon framing? Tim

Tim:
The machinist who was going to quote me for the slider has just backed out.
I'll have to find another machine shop who would want to do this work.
I'll let you know when I find a local shop.... and get a price.

Jim Rogers

hi everyone, timberwrestler is right about the O as the waste symbol with the french standard. You can opt to put the depth of the waste in the middle of the "O" is needed or desired.

As far as his source for the markings I would presume you could find that and a wealth of other information in the French encyclopedia of Carpentry. I can find the actual name out it french if anyone would like to know (I did not want to misspell). However it is probably about 10 volumes and is both rare and expensive. I have looked through it with appreciation at the time required for the information (a little befuddled too). It would be worth the purchase if one knew French, eventhough the illustrations are in builders language. I believe that the information for it was most probably compiled starting with the monks of the medieval ages. Passed on, so some standards have been set.

Here are the two most common ones I use when drafting before lay-out.



The gutterline is the level plane at the lowest working point of a rafter. The centerline symbol is frequently used in timber lay-out.

Very interesting tool Jim. It executed well, it may be worth having certainly. The trouble is often finding a square that is actually square. I have two Japanese squares from Lee Valley which seem pretty good. It sounds like you could make two brackets, one that bolts the two squares together, and one that holds a combination rule to a square. This would allow the TF'R to use his their existing squares and combination rule. That would be a good thing. You know, I have over half a dozen prototype parts/machining jobs that I need done, but don't know any machinist to give the jobs to. Some don't want small jobs, but mine add up to a decent amount and they could use it as filler work - If I could find someone up to snuff. That's the hard part.
Do you know how it(the bearing face measurement) would have been done say 150 years ago?

square rule does not have centered braces....traditionally... think about it.

All rules have exceptions....traditionally.....I thought about it.

I have seen pictures where one timber framer was holding one square to the outside of the timber, another timber framer holding the other square tongue to tongue and using a combination square to check the mortise/housing.
I wanted to be able to do it alone, and not need the extra help....

I do see this tool as being something that we could use for measuring other things and used in other places....

I will be showing a local machine shop the drawings today, to see if they will give me a price....

Tim:
I talked to one old time machinist today and he said he wasn't doing any machine work any more. He was too busy cleaning up his yard to even play with his train models..... wow..... to bad...

So, I was traveling to get some parts for my dump truck and stopped by a regular machine shop, I found in the yellow pages, and showed him the tool.
I've just emailed him the drawings and he said he'd be able to give me a price within a few days.

We'll see.....

I'll stand by. Tim

Centreline layout method works extremely well. Identify the faces of your timber. Level the face of the timber where your joinery will be. Layout centrelines on each end. Join your lines on each face with a chalkline. You now have a centreline on each face if required. If your timbers are not say a perfect 8X8 than you can go from the centreline and snap lines to the outside. All joinery layout begins from the centreline. This system makes it easy to deal with irregularities in timbers.

All,
The French numbering system drawing is in "Traité Théorique et Pratique de Charpente", by L. Mazerolle, available through the Librarie du Compagnonnage in Paris.