Brace problems during a frame fit up test

[Jim_Rogers]

Today I'm fitting up a bent for the frame we'll raise tomorrow.

A fit up is putting everything together in the bent in order to make sure everything will fit correctly on raising day. So that there won't be any slow downs or repairs needed during the raising.

All fit ups are done with the layout side up. All peg holes are laid out and bored from the layout face.

In order to make it easy to fit up the frame, and make minor repairs, I fit up my frames on saw horses in the yard:




Here is a closer shot of the brace in the corner:




While doing a fit up as you have all the pieces together, you measure the outside to outside dimension to see if everything is the right size.

At the tie beam this bent was 1/16th of an inch to small. Across the tops of the post the bent was 3/4" to wide.
At the foot of the post the frame was 3/4" plus or minus to narrow.

Well that sounds like it's easy enough to fix, just move the bottom of the post further apart and the problem is solved.

Right?

Well, what happens when you do that?




If you do that it creates a gap at the shoulder. Why?

With careful measuring I found that this brace was actually cut 2 16ths or 1/8" shorter that the plan calls for. This is what has created the gap.

Other problems:



Above is a shot of the other end of the same brace. It appears that this end was not cut correctly. The angle seems to be off, also.
This is why it's very important to measure with accuracy, and cut properly so that these problems don't happen to you.

Jim Rogers

[Jim_Rogers]

The other brace in this bent seems to be cut better. Here is a close up of this brace at the post pocket:




In the above photo you can see the 3/8" layout line and how it goes right to the pocket corner.
Also you can see through the hole and see that the holes aren't truly aligned.
They are intentionally miss aligned to create a "draw bore" which will draw the frame parts together as the peg is driven into the holes.

Here is a shot of a special brace in the frame at bent number three:




Here is another closer shot from above:




There are two of these in the same bent cut from book matched planks cut from the same log.



They were quite a challenge to get them cut to the right size.

Jim Rogers

[beetle]

Jim,

Good example of how that slight cutting error ( 1/8" ) at the brace compounds the further you go down the post. The longer the post, the more you are going to be wacked out of square.

The same thing would happen if you cut your housing too deep or shallow, as I have done and discussed in another thread.

[Clovis]

Here is an oldie but goodie.

[Jim_Rogers]

Ok, so here's a test.
In the above first post, I mentioned that the bottom of the posts were 3/4" too close together and that the solution was to just move the bottoms out 3/8" each so that the width is the same as the width across the tie beam, which when erected is the position they will be in if the sill pockets are made in the correct location.
But that this opened up a gap at the braces.

I would like you to think about this and post your solutions to this problem.

And the problem is what do we do about the gaps at the brace post, brace tie beam connections?

The reason for doing this test is that during a frame "fit up" you'll find problems, understanding how to solve these problems is very important because some solutions may not be the right solution, because a wrong solution can effect other joints in the frame.

Jim Rogers

[routestep]

Given the beam's shoulder to shoulder length is correct, housings are the correct depth, and the tenon is not bottoming out in the mortise (no need to ask why I think of this problems):

Having been in this situation a few times, having a short brace, I ended up making a new brace. It was the smallest piece of wood. Usless the stock was pretty square I decided to use only a sharp handsaw on the nosing cut. Splitting the thin pencil line counts.

Can hardly wait for other solutions.

[Clovis]

I would be cutting a new brace.

I guess you could add some wedges between the gaps but they might be there for a very long time to show everyone that you screwed up.

Years ago I did my first drywalling job on my own house. I had a small wave in a hidden corner that no one ever saw. Every time I sat in the loft that small flaw would hit me in the head like a frying pan.

[logwalker]

Get over it.   :D

[moonhill]

Well,  the gap is in the none bearing section, maybe I would just live with it.  It being a ref. face, its a good chance it could be on a boarded wall.  So you won't be reminded of it every day.  It would still function.  Now for the why.   Rough stock, maybe a hump at a knot, or a slight curve in the stock.  I at times snap a string line on the 3/8" line ( 1/2" housings or 3/4" for 1" housings)  than lay out the angle off the line.  To be off an 1/8" you could of been asleep at the saw.  ooops wrong picture,  The peg hole is wierd as well now.   Use it as blocking and replace it?   Tim B.

[Brad_bb]

First thought is of course to cut a new brace.  Indoing so, you'd need to align the posts where you want them and measure this particular area to see if you need to customize the brace if the shoulder face ends up not at 45 degrees.  Antother alternative is to grab another brace that you've made to spec and check it's fit.  If when aligned properly you need to compensate somewhere maybe do that.  Third, the brace that is cut wrong... straighten the angle out and fix the shoulder and tenon.  Now you'll have a brace that is to print except that it is 1/8th inch shorter.  Now if you have a post and tie beam that haven't had the mortises cut, shorten each by 1/16th and use the short brace and that way you can use it up and no one will be the wiser.  You then use up all the braces you've cut and only have to fix one end of one.  So what would you do Jim?

[Thehardway]

I would start by checking a couple things.
1. Is the bent overall still square when measured at diagonals?
If the post bowed or twisted since it was cut it could be part of the cause.
2. What does the other brace measure?
Just for giggles I might swap the braces from right to left and left to right and see if it looks closer. It shouldn't but sometimes it is :-\  If that doesn't work and there is still a problem I could cut another brace but if they were of the bookmatched type this is not really an option either.
3. I might ask the question what is the interior and exterior finish going to be?  If structurally allowable I might consider shaving 3/4" off the top of the post above the intersection of the brace and post and then shim between outside wall and post at the bottom to keep the outside wall plumb. If the walls conceal the shimmed portion the 3/4" variance in plumb from top to bottom would probably be less noticeable than the gap in the joint and the owner and/or myselfwould be happier long term
4. Do all the other joints line up properly?
5. How much time do I have?
6. Do I have material to re-cut?
7. How critical is the application (outhouse, woodshed, barn, house, church)?
8. Is this for myself or "professional"?
9. Will it cause additional problems if left?

I have learned quickly that when a green timber that  is cut on a 45* angle shrinks, the angle changes and can make things squirrely in preassembly and fit up. This can only be prevented by compensting for shrinkage in green wood or using dried and stable timbers.  You may cut a new one the right length that fits perfect and go back 5 years later and find a gap anyway due to shrinkage.

Obviously the right thing to do would be to re-cut and make everything correct including the tie-beam that is a 1/16 to short but time and materials may not permit nor the application justify.  Leaving as is may add "character" to the frame and as long as it does not affect other structural or fit/finish issues it might be best to leave alone or apply one of the above remedies.

Anxiously awaiting the "right" answer.

[Jim_Rogers]

Anxiously awaiting the "right" answer.

Well, I don't know if there is any one "right" answer.
I just wanted to see how many other ways this problem could be solved.

I think it was Tim Beal who first asked what bent was in it and or would it show if the brace was just shimmed between the shoulder and the brace mortise housing.

If it was an end bent then just shimming the brace at the housing and adjusting the peg hole would have made the bent the correct width. Or at least the same width top, bottom and at the tie (still 1/16" to narrow).
To be truly correct the tie should be shimmed out first and then the shims for the braces could be created and slipped in.
This would be the easiest if it's a gable bent as most of these shims would not show.

As this is just an out building, not a house or a church, then simple solutions would work.

Re-cutting a new brace would also work.

Saving the short brace to use else where, custom fit to two other mortises, would be a good way to use up this shorter brace.

And to tell you the truth this building was erect here in my sawmill yard, sold, disassembled, moved, and re-assembled, and enclosed. And I don't remember what, if anything, I ever did about that brace being out of line. Probably nothing, other than moving the peg hole so the building came out square.

But this was a good test. :P

And you all passed...... ;D ;)

[moonhill]

Well....if it was a church wouldn't you be forgiven for your sins.   Tim B.

[Thehardway]

Jim,

Do you have much call for those bookmatched naturally bent braces?  Can you tell us how you went about milling them?  How did you dog them down?

By the way I enjoyed your little test. 

Thanks.

[matt eddy]

i agree with Tim, it will still function and after a year of drying you usually get some gaps anyway.  the only person who will notice that gap is fellow timber framers.  wood is perfect, and like Tim mentioned your boarding is going to cover it to.  but anyway Jim good luck with the rest of the raising.
Matt

[shinnlinger]

MY 2 cents would be to  leave it. 

A frame is not judged on one joint or timber, but the overall aesthetic.  I think it is a poor use of resources to re-cut a brace that is otherwise structurally sound.  Wood, by its nature, is not a perfect material, and speaking for myself, I am not perfect either.    When I see mistakes I have made it reminds me to do better next time and how far I have come.  Any one else who looks at that joint though(If they even do) wont even notice it.

On a reused barn frame especially, it is these mistakes that give it its character.

However I like that this thread, because it  points out that cutting windbraces needs to be fairly precise if you want it to look perfect.

[slowzuki]

My shop is not timber framed but just a metal connector post and beam.  I made some mistakes in the math on the first two bents (9 total) and we decided to leave them.  It has caused a trickle down of trouble since and I wish I had done it right.  People can't see it but when I started the kitchen, the stress made the leg have a slight bow to it.  Also the bathroom wall isn't square in that area.  The second floor is tweaked out of square in that area.

My excuse at the time was a building like this isn't meant to be perfect, but I tell you, an extra hour at the time would have saved hours of head scratching.

[shinnlinger]

Slow,

I agree, square it up...My point was if the brace angle does not match the post, but is other wise sound (and this to me means square also) go with it.

YOu may consider making your mortises longer to the inside or outside as the case calls for to allow the brace to sit at the correct angle.  a bit of the mortise will show obviously, but it will be alot less noticible than an out of alignment brace.