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Lean-to Questions

Started by rbowie, January 11, 2013, 01:29:47 PM

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rbowie

I'm starting small with my first timber frame project.  Looking to add a lean-to to the side of my garage.  I am planning on lag bolting one side to the garage wall which should eliminate the need for bracing in that direction. 

I have a couple questions.  First, of the two options I'm showing in the picture, is there one that is better than the other? 
Second, does anyone see any issues with the rafter connection that I've shown?

Thanks,

Richard

  

  

  

 
1 Sawhorse in and the addiction has begun

Jay C. White Cloud

Hi Rbowie,

Looks good over all, and should be fast/fun to cut.

  • Option #2 is real nice. I would not consider option #1 as it is configured, (poor ledger connection-not as strong as #2.)
  • If you want to try to do braces for the practice, go for it, other wise you could use a pass through brace, and be fine for this structure.
  • Place rafters on top of rafter plates in notches and peg/lag from top.

Good Luck!! and have fun.

Regards,  jay
[/list]
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

Thanks for the recommendations Jay.

By "pass through brace" are you meaning use a through mortise on the post?

Richard
1 Sawhorse in and the addiction has begun

Jay C. White Cloud

Hi Richard,

Yes just a simple through mortise.  For your project 40 mm x 150 mm (1.5"x6") would be fine.  You would cut the mortise at 190 mm (7") high and wedge from the top. 

The one thing I did forget to mention, is making the tenons on the beams that connect your wall bent to existing architecture could be pass through tenons/or free splines and wedged, on the free standing bent.  Below are some example photos of free spline joinery I just did for a pasture run in shed.


 


"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Dave Shepard

Nice drawings. I like seeing hand drawn stuff. 8)
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

jueston

jay,

in the piece in that picture are they both the same species of wood or is it a softwood beam and a hardwood tenon?

Jay C. White Cloud

Hey Justin,

I think I owe you and email too. 

The beams, 5.6 m (18'), hand been some reject hemlock we had sitting around and didn't want to mill anymore 6 m plus.  For ease of assembly and tenon strength we used some really nice sugar maple.  There was three of them in the frame, with three free tenons.

I'll send an email soon.

jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

Jay, those free splines scare the bejeezus out of me with my skill level.  I think I'll take your advice and use a through mortise for this first project. 

Do you typically use free splines when you aren't able to achieve adequate tenon strength from the beam wood species? 

For the through mortise wedge, should I be using hardwood?  I will be using lodgepole pine for the remainder of the frame.

Dave, thanks for pointing out the hand drawings....I think it's a dying art!
1 Sawhorse in and the addiction has begun

jueston

Quote from: rbowie on January 11, 2013, 09:44:08 PM
For the through mortise wedge, should I be using hardwood?  I will be using lodgepole pine for the remainder of the frame.


you can do the full mortise with pegs or with a wedge depending on what kind of look you want, but either way the pegs or wedge should be made out of dry hardwood, you don't want those to shrink. as the green wood dries around the dry hardwood it will tighten up a little, but if the pegs or wedge was to shrink it would create a loose joint and reduce the strength of the frame.

Jay C. White Cloud

Hey Everyone,

I did forget to comment on your drawings, I was a little taken back by seeing some nice isometric grid paper in use, that was cool.  I make anybody I teach learn to draw and CAD both equally well, not to mention good drafting calligraphy.  I'm almost out of iso paper, where did you get yours, online?

Now for your frame, don't be scared of nothing, that joint is way easier than it looks.  I'm not saying you have to use it, but it's not really that hard.  I will share the caveat, that I use line layout systems, not mill, or scribe rule, which makes layout much more accurate and gives you the option of employing templates more readily.   That ties into your bracing question.

In European frames, scribe rule and edge rule are the layout methods and oblique bracing is the bread and butter of the craft.  Now, in the older-original methodologies of the craft, going back thousands of years, like in most of Asia's history of timber architecture, Center Line or line rule layout is the the norm and bracing a frame is achieved through members running horizontally, rendering a frame solid but more flexible in seismic events.

QuoteDo you typically use free splines when you aren't able to achieve adequate tenon strength from the beam wood species?

Yes that is one of the reasons. There are others reasons to numerous to list here that are specific to different circumstances, like too short of beams/logs, ease of frame assembly, mixing species to render different effects in the joinery, etc.

QuoteFor the through mortise wedge, should I be using hardwood?  I will be using lodge-pole pine for the remainder of the frame.

As Justin pointed out, the pegs and wedges should be of dry hard wood.  However, if you don't have dry, just be aware that the wedge will shrink and need to be re-tightened.  One trick that we still do to this day, is pop them in 150 to 200 degree oven.  This drys them out fast, then we place them in oil.

Ah yes, Lodge Pole Pine, beautiful Pine species and perfectly acceptable for your frame.  Some trees of this species can have pronounced twist, try to avoid them and don't worry it is obvious.

Now your bracing through mortises, if you choose to use them, that is really simple.  On top of your post, you are going to have your rafter plate, (I would recommend housing the post into it,) from there come down 100 mm (4") and this will be the top of your connecting girt that ties to the other post against the preexisting architecture.  From the bottom of the housing for the connecting girt, you need to come down a minimum of 100 mm (4") and place your through mortise for the horizontal brace beam.  As you get closer to making your final choices, I would recommend making final elevation drawings, a cut list and joint maps.  I would also avoid using a tape measure, make a story pole instead.  Good luck, let us know if you have more ideas/questions.  Can't wait to see photos of finished frame!  See drawing of Bent Elevation for and example below:

"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Jim_Rogers

One thing that worries me about your design is the risk of the post splitting as your tie is too close to the plate.

There should be at least 8" of post between the top of the tie and the bottom of the plate.

This is the reason why:



You should consider moving the plate up or the tie down until you have at least 8" between the two.

Just my thoughts on your design.

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

Rooster

Jim,

If the top of the rafter is secured to the existing building, will the rafter still push the top of the post over causing it to split?

Didn't you just post this photo in a different thread that will have the same issue? 
I've been kind of slow these past couple of days...I must have missed something! This is me, dazed and confused... smiley_mad_crazy


 
"We talk about creating millions of "shovel ready" jobs, for a society that doesn't really encourage anybody to pick up a shovel." 
Mike Rowe

"Old barns are a reminder of when I was young,
       and new barns are a reminder that I am not so young."
                          Rooster

Jay C. White Cloud

Unless you get an "awful strange wind," as Ed Levin put it, you do not get out ward thrust loads in any assembly that has full ridge support, as you do in most Asian designs and porches, which is what you have in your case.

Now with that said, Jim's observation about your tie beam's proximity to the top is dead on, with or with out "out ward thrust."  You would be better to capture the top of the post with some form of three way tying joint, or moving the tie beam down 200 mm (8"), but that is only if you are not going to use the through tenon I suggested.  With the through tenon on your tie beam, you will capture the wood that could shear at the top of the post.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

piller

Great thread here.

Jay:  how do you keep your mortiser stable when mortising at angles to your workpiece?   
   
Please post more info/examples about the horizontal through bracing, I'm not familiar with that and it seems interesting.  Do you have to use wedges which can tighten the joint to compensate for shrinkage?  I would think that the joint would need to be kept quite tight and or you would need a wide post to provide lateral bracing.

Also, you mentioned "Place rafters on top of rafter plates in notches and peg/lag from top".  Could you elaborate on this connection, would you notch both the rafter and the plate?

I'm not going to throw out my tape measure but I'll have to look into this story pole thing. 

Thanks,
Chip




Jay C. White Cloud

Hi Chip,

A few folks have ask me to expand that discussion and a few other things I've mentioned.  I don't want to do it on this post thread of Rbowie's detracting from his project discussion, so when I get a chance, I have several folks that have also asked about Asian timber framing, so maybe a new post topic is in order, "Asian Design Methodologies in Timber Framing."  Look for that.

QuoteAlso, you mentioned "Place rafters on top of rafter plates in notches and peg/lag from top".  Could you elaborate on this connection, would you notch both the rafter and the plate?
This I should answer.  You just notch the rafter and ridge plates.  It does not have to be very deep, maybe 30 to 40 mm (1.25" to 1.5") in this application, for this design.

Regards,   jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Jim_Rogers

Quote from: Rooster on January 12, 2013, 01:41:18 PM
Jim,

If the top of the rafter is secured to the existing building, will the rafter still push the top of the post over causing it to split?

Well, the correct answer to this question is, it depends. It depends on a lot of things. First of all his location is Calgary, Alberta, Canada, and I don't know the snow load there, but if the snow load is a lot, maybe.

Next, he shows the rafters attached by two different methods and I'm not sure if the screws will take the snow load.

Also, he shows this lean-to roof lower than the garage roof. We don't know the make up of this other garage roof. Is it asphalt shingles or metal? If it's a metal roof, or even if it's an asphalt shingle roof; we have to consider snow sliding off this upper roof onto this roof. That load could be a lot when that happens. And it will happen all of a sudden.

And, we don't know if this lean-to is going to be open or enclosed. If it is open then it maybe loaded with some wind load should one of Ed Levin's "strange winds" occur.

Quote
Didn't you just post this photo in a different thread that will have the same issue?

I'm not sure about another thread with this photo in it as I just uploaded it for the tie beam question.

I hope this has helped you to understand that we need to consider everything very closely.

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

Jay C. White Cloud

Hey Rbowie,

Jim's recent post responding to Rooster, is one you should read several times and ...really...consider all the factors.  These are exactly the kind of, "what if's," Ed was taking to me about.  You really have to take a step back and consider,   potential loads.  You have a small project and it probably isn't going to be subjected to some of the events I have running through my "noodle," but Jim's points are really important to always consider on any design.

Always take a, "what if this happens," approach to a design, then consider if you can live with the outcome.  We have all over built things at times but "under building," something can be disastrous; not that you small project is anywhere near that.  You would probably be fine if you had just built it the way you originally drew it, but if one of the cases that Jim brought up did happen, you would most likely loose the frame because the ledger and rafter connections is your weak spot.  That's why I liked your option #2 free standing design with some "tweaking."

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

Jim, the structure will be located in a zone with snow loads of 35.5psf.  And you are bang on that I need to factor in the snow from the existing garage roof.  It's asphalt shingles and an approximate 6:12 pitch.  I will essentially double the snow load on the lean to.

Further, the lean-to will be open and is on the west side of the house which will leave it exposed to the prevailing winds out of the NW.  Also need to factor in uplift on the underside of the roof due to wind.

For the rafters, I will follow Jay's advice and notch them into the top of the rafter plates and secure with lag screws.  I'm also considering putting a bird's mouth at the lower rafter plate to eliminate the need for the lag screws up top to be in any significant shear.

A light bulb also went off about the bent that is up against the existing architecture.  It didn't have any bracing.  I think I will put the same bracing in both bents so that I'm not expecting the garage wall to take the snow load at all. 

I will do up a fresh set of sketches and post them to reflect this. 

Last thing is that I will definitely create a story post for this project as I will have 4 virtually identical posts.

Richard
1 Sawhorse in and the addiction has begun

timberwrestler

I agree with Jim and Jay's earlier comment about moving the tie down a little.

The only other thing I'd do is move the upper garage wall ledger down, and have the rafter sit on top of it.  It's easier to cut, and is much better for transferring the load.
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rbowie

Alright, I've updated my sketches to reflect all the fantastic feedback.

I've decided to use the through mortise with wedges to capture the top of the post in order to prevent the post from cracking.  I've also moved the tie beam down 4" from the top of the post.

I've moved the rafters so that they are on top of the rafter plate rather than in the side.   

  

  

 
1 Sawhorse in and the addiction has begun

Jay C. White Cloud

Hey Rbowie, 

Looks real good. Consider the following:

You do not need to wedge and peg through tenon.

One wedge per tenon will be fine for this frame, (unless you like the look of two.)

There needs to be a least 100 mm or better 150 mm of wood past the wedge mortise on the tenon, (4"-6")

You should extend the rafter tails to make the drip line of the structure come past the through tenons at least 300 mm (12".)

Other than that, It looks like your ready to make a story pole, some templates and start cutting.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

The build has begin.  I've got a stack of pine in the garage and I've started making wood chips.

I'm trying to be as methodical as possible to begin with.  The first through tenon has been a challenge in getting it dead flat due to the length.  It will be 11" long as I'm using 6" timbers.  I am using a 1" housing and since it will be a wedged through tenon I have allowed for 6" extension beyond the post. 

Is there any tips to help in getting the reference side of the tenon bang on?  Especially with the longer tenon.  The 5" tenon at the other end of the tie beam was far easier to cut.



  

  

  

  

 
1 Sawhorse in and the addiction has begun

Jim_Rogers

To insure your tenon is parallel with the layout side/reference side you can place your framing square over the end and set you combination square on the top of your framing square set to the thickness of the body of the framing square (2") and the offset of your tenon (1 1/2" or 2").

This will tell you if the tenon is parallel with the side of the timber:



 

If there is a gap between the framing square and the combination square then you haven't shaved off enough. If there is a gap between the bottom of the combination square's ruler then you have shaved off too much. Be careful next time.

To check the tenon is offset the correct amount at the shoulder use your framing square again. Like this:



Here you see the blade of the framing square is set on the tenon, and the try square is sliding across the timber's surface toward the square. If it hits the square then the tenon is not correct. If it slides over and there is gap you took too much off. It should slide over and touch the square as it does.

Always cut the offset side first. Then cut the tenon to thickness taking off the back side until the tenon is the right thickness. Use a caliper gage to check thickness.
Like this:



 

Set the caliper gage like this:



 

Hope that helps.

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

Dave Shepard

That rounded through tenon with two wedges makes it a Dutch leanto. :D
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

Rooster

We call it a "Leaning Dutchman"...."Georiënteerde Nederlander"

8)
"We talk about creating millions of "shovel ready" jobs, for a society that doesn't really encourage anybody to pick up a shovel." 
Mike Rowe

"Old barns are a reminder of when I was young,
       and new barns are a reminder that I am not so young."
                          Rooster

rbowie

Thanks Jim.  That definitely helps.

I was also unsure if it was typical to reduce the through tenon down to 5 1/2" for the 6" timbers.  I have seen it done for most other tenons but I wasn't sure if the wedged through tenons would be treated the same way.  I'm going to start cutting the mortises soon and I don't want to cut them all 1/2" too large.
1 Sawhorse in and the addiction has begun

Jay C. White Cloud

Hey Rbowie,

Looks like you are on your way.  The process itself will teach you a lot about this craft.  It appears you are using edge rule.  With that method you do reduce to "an ideal timber," in side the wood you are using, so reducing down to 5.5" is proper.

This also leads to your other questions.  There are many techniques for keeping tenons strait.  Since you are using "edge rule" layout, I would follow Jim's advice for both alignment and tracking thickness.

If you used "line rule," you would use templates for all your joint layout and reference off a snapped ink line on the timber.  The line runs from end to end, so your joinery is always in line, unless you choose to offset it for a reason.  The templates work in concert with your story pole.  You only really layout your joints once, on the template material.  The story pole shows you wear to put the joint's reference marks on the timber. Then the templates reference those marks and are aligned with the snapped ink line.

Regards,  jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

Many hours spent in the garage this weekend.  I am definitely not breaking any speed records but the learning curve is steep!

I've adjusted by method for finishing off the tenon faces and I've started using a series of planes.  Basically I make my shoulder cut, then I remove the bulk of the waste with a chisel, flatten to within 1/8" with a slick.  Then I use a wooden rabbet plane against the shoulder to bring the face to precise measurement.  After that I use a small block plane or a #4 smooth plane depending on the size of the tenon to bring the remainder of the face to the same level as the the rabbet plane surface at the shoulder.  The result was a remarkably uniform tenon compared to the previous attempts.  Not that the others were terrible, but the difference is noticeable.

Next step is to start cutting braces and brace pockets.  Should be interesting!

  

  

  

 


 

Had some help from the shop dogs too!
1 Sawhorse in and the addiction has begun

Brian_Weekley

Looks like you are doing a fine job.  Nice helpers too!
e aho laula

Jay C. White Cloud

You are doing great...speed is not the point now, learning and refinement of method is.  ;)  Good Job!!
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

jueston

looks like your really coming along. well done!

swampfox

It looks like you haven't cut your interior post or plates yet so I will leave this with you.  Do as you like.

Do you not want an overhang at your shed roof eave?  If you do, you could just say, move your rafter to have "X" height above plate (birdsmouth) and move your top plate at existing up the same amount.

Nice work.  8)

rbowie

You're right swampfox, I haven't cut the interior posts or either plate yet.  Interior posts are next, then plates.

I'm a bit confused about what you mean about moving the plate up.  Are you able to provide a sketch?
1 Sawhorse in and the addiction has begun

swampfox

Sure.

Think of it this way.  You have your rafters top edge dying at the outside upper arris of your outer plate.  If you want to have an overhang there your rafters will have to ride over said plate and have a birdsmouth.

So, with this in mind imagine raising the interior plate and rafter up towards the sky together.  You will only have to go a little bit to get your rafter's top edge now riding over the exterior plate.  The pitch stays the same.  From there you would just have raise the shoulder of the interior post the same amount to reach the plate you just raised in elevation.



OR, you could change your pitch of your rafter too, if there is not enough room above.

Rooster

As Orville said to Wilbur, "You're Wright!"
"We talk about creating millions of "shovel ready" jobs, for a society that doesn't really encourage anybody to pick up a shovel." 
Mike Rowe

"Old barns are a reminder of when I was young,
       and new barns are a reminder that I am not so young."
                          Rooster

Jay C. White Cloud

From my post reply #21:
QuoteYou should extend the rafter tails to make the drip line of the structure come past the through tenons at least 300 mm (12".)

and I still feel that way about it... ;) ;D

Swamp Fox just snuck into my office and took the sketch off my desk and posted it here for you to see what I was get'n at, he's a Fox so it makes sense.  :o :D :D :D  good job S.F. with the sketch.
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

rbowie

Makes perfect sense.  Thanks gents!
1 Sawhorse in and the addiction has begun

rbowie

This weekend involved cutting braces.  Managed to get all the braces cut and one brace pocket.  Turned out not too bad.

I was wondering if anyone has any advice on how to flatten out the bottom of the brace pocket.  With the tight quarters I had a very difficult time getting if flat and smooth.  Any hints?

The brace pockets are cut 1/8" deeper that the tenon so that it doesn't bottom out.


  

  

  

  

  

 
1 Sawhorse in and the addiction has begun

Rooster

Quote from: rbowie on February 11, 2013, 12:18:07 AM

I was wondering if anyone has any advice on how to flatten out the bottom of the brace pocket.  With the tight quarters I had a very difficult time getting if flat and smooth.  Any hints?

The brace pockets are cut 1/8" deeper that the tenon so that it doesn't bottom out.


The nice thing about timber-framing is that often times there are areas inside joints that will never be seen once the frame is assembled and raised.  I'm sure that you want to be thorough and accurate when cutting your frame, but you do have some tolerances built in so that you don't have to worry about what the bottom of the mortise looks like. As long as the overall depth is deeper than the tenon..then you're good.  This way the time you would have spent making the bottom of the mortise completely flat, you could start your next mortise.  At a certain point, you will have cut enough mortises not to care any more.  I think the number for me was around 3.... ;)

And if anyone is critical about the bottom of your mortises...

We have a saying for that.

"Then they don't have to come over and drink your beer!"

Sober 22 years,

Rooster
"We talk about creating millions of "shovel ready" jobs, for a society that doesn't really encourage anybody to pick up a shovel." 
Mike Rowe

"Old barns are a reminder of when I was young,
       and new barns are a reminder that I am not so young."
                          Rooster

jueston


Jay C. White Cloud

Morn'n Rbowie,

Looks like some beautiful work from were I'm sit'n.  I would take you on as a brace man any day...looks real good.  Brother Rooster is spot on, because of my back ground, most of the insides of my joints have little scallop marks because I use a "tea house," chisels so often.  Some folk really have issues with making all there joints real neat and pretty...inside and out...we call them "ARTWitts" - (anal retentiveness timber wrights.)   :D :D :D  Only part that needs to be tight is the part you see and the part that is doing "the work."  I go 10 mm to 15 mm (~.25" to .45") past the required depth most of the time.  Now if I still had it or could find another timber framing version of it, I would sometimes hit certain joints with a nice "Goose Neck," chisel.  That is what they are designed for, cleaning the bottom of mortises, but most times it is production work, and once the chain mortiser is done, you move on.  In a production shop, you should be able to comfortably layout and cut a minimum of 4 braces and hour to hour and a half, often including the mortises if the timbers are flipped your way and know one else is working on them.

Something else to consider at this juncture is "wedging."  Braces really should not be "trunneled," or "pegged," they don't really benefit much at all from it, and in most cases, if the frame was overloaded for some reason, the relish would fail anyway.  So I would recommend, in your case because they are "housed braces," enlarging the mortise on the inboard side (the slop,) about a 15 mm to 20 mm  (~.5" to .75") and this is were the wedge is put.  Snugged in, not over pounded with about 40 mm (1.5") left proud.  Some folks only do it at the bottom, since the joint only works in compression anyway. 

Keep up the good work!

Regards,

Jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

jueston

Quote from: Jay C. White Cloud on February 11, 2013, 09:21:16 AM
the joint only works in compression anyway. 
Jay

I read this sentiment in one of the books you recommended, and I assumed that Asian design were designed to use the braces only in compression but that a pegged braces in American designs worked in both compression and tension.

is the reason they can not work in tension because the joint is not strong enough in that direction?

Jay C. White Cloud

Hey Jueston,

Been a while.  Actually, you have it a little reversed.  Most of the brace work in European frames, only work in compression.  Pegging braces is a regional and somewhat modern affair, and many vintage frames don't have peg braces, wedging is better.  They just don't have enough relish to be pegged, and only work in compression.

Asian bracing, both horizontal and some of the obliques, work in both compression and tension, (even thought much of the english translated literature has misled that fact,) and when a brace is working in both compression and tension, it is acting more as a strut than a brace.  Does that help?

Regards,

jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

jueston

I understand, and will say that every time I see a brace I question the amount of wood on the other side of the peg, and wonder how much tension it would take to tear the tenon apart. but if you sought to use the brace in tension, couldn't you just make the tenon longer to allow for a stronger joint?

Jay C. White Cloud

QuoteI understand, and will say that every time I see a brace I question the amount of wood on the other side of the peg,
That's good, you should and it shows you are being observant.

Quotewonder how much tension it would take to tear the tenon apart
Very little to none at all, that is why pegging is futile in most cases.

Quoteif you sought to use the brace in tension, couldn't you just make the tenon longer to allow for a stronger joint?
Ah, now your thinking.  Yes in some cases, you will find oblique bracing in large gate assemblies to shrines and temples, that have a brace that is working in both compression and tension, making it a strut, more than a brace.  If you are working with your own designs there are other viable options beside trying to make a tenon longer that are easier to facilitate and function better.

Regards,

jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

Jim_Rogers

Tension braces have longer tenons.

Pegs in braces are usually there to hold the brace in place while the frame is being raised.

That is why some "historical/older" frames don't have pegs in braces. While they were being raised they were held in by ropes or other means.

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

Dave Shepard

Braces are also typically used in opposing pairs. When one brace might be in tension, there is the opposite one in compression that should be taking the load.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

rbowie

Did the first post to beam fit-up with brace.  Very excited to see that it all fit snug and square.

Couple questions:
1. Trunnel sizing.  Since I'm using 6" timbers, 1.5" tenons, I'll use 3/4" trunnels.  Is this correct.  I seem to remember the rule of thumb being the tenon is 1/4 the size of the timber and the trunnel is 1/2 the size of the tenon.
2. Is there any rules of thumb for the wedged tenons on the tie-beam?  Just wondering what a typical slope would be for the wedge and if you also slope the mortise?

Thanks,

Richard


  

 
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