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Layout of braces with crown

Started by AMB30518, April 15, 2012, 02:42:54 PM

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AMB30518

Hello everybody,
I am working with 6' and 8' 6"x6" brace stock, some with crown. Should the crown be to the inside of the "triangle" (toward the post) or outside of the triangle between the bent openings or toward the inside of the structure? Does it matter?
The braces are housed, some 1/2" and some 1".

Your advice is appreciated.
Aaron
I did some chainsaw milling, learning sketchup & timber framing for home projects but not an expert..... I learn as I go and go as I learn.

Aaron

Jim_Rogers

When you layout the brace, you use a layout line. This line is the diagonal of the right triangle.
If your braces are housed 1/2" then the layout line is 3/8" off the reference edge.

The layout line is straight. So it shouldn't matter if they are crowned in towards the corner or out. As you are going to draw your 45° angles off of your layout line and not off the actual bend surface of the timber.

If it was me, I'd crown them in towards the corner so that you'll get more clearance from the belly of the crown. Similar to the way we layout a brace on curved stock.

I hope you understand what I mean by this.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

AMB30518

Jim thanks for the response, I think I understand and will try this layout method in a couple of days. Square rule layout, correct?
Would the 3/8" line distance be different for a 1" housing?
And would the line distance from reference edge be different for a 60 30 degree brace?
Or is a straight "reference/layout line" the main objective?
So I'm guessing there is no structural strength preference.
I planed the cants today, smooth but not straight or square all around, and plan on laying out in a day or two.
I'm working on a setup system to plane straight and square with a modified 12" benchtop planer.

Thanks again.....
I did some chainsaw milling, learning sketchup & timber framing for home projects but not an expert..... I learn as I go and go as I learn.

Aaron

Jim_Rogers

Aaron:
If the housing is 1" then the layout line is not 3/8" it is 1/2".

Although I'd have to check to be sure.
You said a 60° brace.

What is the layout exactly? Please tell me the tie and post dimensions, so that I can draw it up to be sure.

Are you doing a 3-4-5?

Jim Rogers

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Dave Shepard

Wouldn't it be 3/4"? Twice the housing, twice the distance off the reference face? Or, technically, the housing divided by 1.4141? So, a 1" housing would be .7071"off the reference.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

Jim_Rogers

Dave:
I think you're right but I need to verify that by actually drawing the post, tie beam, and brace at the angle and lengths he is going to layout.
Once I do that I can give him an accurate answer.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

AMB30518

Jim and Dave, I appreciate your help. I'm a beginner and have lots to learn about what I'm trying to do and hope to not make it more complicated than needed.
I just checked my drawing and seems I made a mistake and said 60 deg. instead of 30 deg. brace, which I think is correct and the way I have it drawn in the drawing Jim posted for me 8-10 days ago. My R-V carport sketchup drawing, in the drawing & plans section.
I'm talking about the 4 rear side outer braces which are 6"x6"x8' 6 1/2" long, a 6"x6" post and 6"x6" tie beam. I can't post the pictures of joints like others can. Sorry.....

I drew the braces more vertical because it was my understanding that under compression there would be more downward force vs horizontal. Is that correct?

The crown & belly in my brace stock is only 1/4"-1/2" over 10' length. Maybe that is not too much to worry about in a carport but the long term goal is to build a cabin/home. I like the curved live edge and book end looking braces and hope to learn that too.
I also took a measurement from the outer face of the brace to the corner of the 1" housing and it was 7/8" at the post and 1/2" at the upper tie. I guess because of the 30 deg instead of a 45.
Jim, no I did not do a 3-4-5 layout. I just drew the brace stock, tilted it to 30 deg and drew my joints.

Ahhh, the sign of a real amatuer is showing now! And I admit it  ;D
But hay..... I'm trying to learn and am making progress. I am also reading back posts and am on page 20 now.
Thanks Jim and Dave
I did some chainsaw milling, learning sketchup & timber framing for home projects but not an expert..... I learn as I go and go as I learn.

Aaron

Mad Professor

You can layout irregular beams/braces exactly using a compass/divider.

I posted how to do this for 45 degree braces.

You can do this for 3 4 5 braces but the layout is different for the mortise and tenon.

An advantage of the 3 4 5, is that it exactly squares the beams it is bracing.  Otherwise, you use a 3 4 5 to square the beams before locating the mortices and cutting the braces to length.

All you need is a compass/divider, chalkline and plumb bob. Mark out your reference circles that will be the basis of your joinery/sizes for the frame.  Old frames had these marked on a prominent beam if repairs were needed.  There may also be "stars of David" scribed onto the beams, that was a way to achieve exact 90° angles for posts and tie beams.  These were also laid out with simple geometry.

Sorry for hijacking the thread,

I'll work on a post for a 3 4 5 layout of a brace using a compass/divider

AMB30518

You didn't hijack the thread Professor. Thanks for your input.
I would like to see your layout with a compass & divider because I want to learn to do some large limb or bent logs for braces. But I also realize I am at the beginning of a large learning curve.
We didn't do any of that in the 2 workshops I attended.

I did solve my immediate problem with the project at hand by working out some details of the modified bench planer (mentioned above) to get my brace stock straight and square within 1/32" - 1/16" and some dead on square. The modification went better than expected.

I will probably start a thread of that before long since someone else may be interested too.
Thanks again and I'll look for your thread.
I did some chainsaw milling, learning sketchup & timber framing for home projects but not an expert..... I learn as I go and go as I learn.

Aaron

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