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Another Jack Sobon Shed. :)

Started by trigger_andy, March 18, 2020, 07:32:37 AM

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trigger_andy

Hello all,

Ive been interested in wood work for some time now. Ive been Alaskan milling for 5 years and 18 months ago I purchased a Logosol B751 Bandsaw, which I love. Ive made a few small projects, a Rocking Horse, Coffee Tables etc and a few weeks agob I build a Log Deck for my Bandsaw using a new (to me) Makita Chain Mortiser. I have wanted to do my own Timber Framing around my Property for at least 5 years and now is the time for me to jump in. I bought Jack Sobon's Timber Frame Construction and Timber-Framed House books and really have enjoyed reading through them. 

So like many here, I want to start with my own shed that Jack has in the book and take things from there.

I have access to lots of Softwood that Ive felled on my own property, mostly Stika Spruce and some Scots Pine. This is cut to the maximum my Mill will cut, which is 4.7m, or 15'.5". Which is obviously shorter than the required 16'+. Although I could, and probably should make my first Timer Frame project out of Soft-Wood I also have access to English Oak (White Oak) but only in lengths of 9 foot. Id love to use my Oak for the Frame, but the length is obviously a problem. 

Would it be acceptable to joint the beams? Maybe a Lap Join the Sill and maybe Scarf Join the Plate's? 

Ive had a look at a lot of the other threads and found them fascinating and cant wait to start my project. Out of interest how long does the Shed take to build from start to finish, excluding the work not covered in the book? I know this is a 'how long is a piece of string' question, so any actual examples would be great to get a rough idea. 

With this Corona Virus doing the rounds and being on Lock-Down I might have more time to dedicate to this project than Id normally have. :D 

Carpenter

     Yes, you can scarf the plates, and half lap the sills.  It's done quite a bit in larger buildings.  It's probably not often done in a Sobon shed because most people can get full length timbers.  But, if you want to scarf them to make use of shorter timbers it would be fine.  Just keep in mind scarf placement.  Also, keep in mind that any time you scarf join a piece of wood you are giving up some strength over a full length beam.  

     For sills over a continuous foundation scarf placement is not critical and a simple half lap screwed together, or even nailed together will work fine.  As all of the weight is being transfered straight to the foundation the only thing the scarf joint is doing is to combat any side strain (rolling) that the sill might have on it, and tie the timbers together to make them act as one.  If you are building the shed over a pier foundation obviously scarf joint placement as well as the type of joint chosen will be much more critical.

     As for scarf placement in a plate, I think this is covered in one of Jack's books.  But, over a brace is typically considered to be the best scarf placement.  You have upward thrust from the posts, and downward pressure from the weight of the roof, a certain distance from the post is where the pressure is somewhat balanced which happens to typically fall over a brace.  (I realize that is not a very good explanation, It makes so much more sense in the book, I think it's in one of my Sobon books.)

     Also, the strength of the scarf will come down to how well you can cut the joinery.  They are not super difficult to cut, and if you cut and prefit the scarf first before cutting any of the other joinery, (even if you totally mess it up you can redo it).  But, if you get it close, it's pretty easy to tighten them up with a handsaw.  My point is, don't be intimidated by the scarf joint.

     You  could also resize the shed.  The Sobon shed is a pretty basic frame, easy to modify.

     Time wise, we estimate 3 hrs per joint.  That is both the mortise and the tenon of an adjoining member counting as one joint.  Also, that's timbers on the saw horses, the layout, joints cut, pre-fit, labeled, peg holes drilled, oiled, stacked, and banded for shipping.  I'm typically under the 3 hrs, but most people are typically over.  Another time estimation technique is to estimate a day per major timber, which is also going to get you in the ball park.  




Good luck with your project!

     

Dave Shepard

If you are going to scarf, then you could go bigger. For just the four beams, I'd try to find a way to get the full length.

I've done the 12x16, and also a 16x20 version. I cut this 16x20 in 80 hours with hand tools, including boring all mortises with a hand crank boring machine and riving all the pegs. All peg holes were bored with an 18volt cordless drill.


Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

trigger_andy

Quote from: Carpenter on March 18, 2020, 11:36:35 PM
    Yes, you can scarf the plates, and half lap the sills.  It's done quite a bit in larger buildings.  It's probably not often done in a Sobon shed because most people can get full length timbers.  But, if you want to scarf them to make use of shorter timbers it would be fine.  Just keep in mind scarf placement.  Also, keep in mind that any time you scarf join a piece of wood you are giving up some strength over a full length beam.  

    For sills over a continuous foundation scarf placement is not critical and a simple half lap screwed together, or even nailed together will work fine.  As all of the weight is being transfered straight to the foundation the only thing the scarf joint is doing is to combat any side strain (rolling) that the sill might have on it, and tie the timbers together to make them act as one.  If you are building the shed over a pier foundation obviously scarf joint placement as well as the type of joint chosen will be much more critical.

    As for scarf placement in a plate, I think this is covered in one of Jack's books.  But, over a brace is typically considered to be the best scarf placement.  You have upward thrust from the posts, and downward pressure from the weight of the roof, a certain distance from the post is where the pressure is somewhat balanced which happens to typically fall over a brace.  (I realize that is not a very good explanation, It makes so much more sense in the book, I think it's in one of my Sobon books.)

    Also, the strength of the scarf will come down to how well you can cut the joinery.  They are not super difficult to cut, and if you cut and prefit the scarf first before cutting any of the other joinery, (even if you totally mess it up you can redo it).  But, if you get it close, it's pretty easy to tighten them up with a handsaw.  My point is, don't be intimidated by the scarf joint.

    You  could also resize the shed.  The Sobon shed is a pretty basic frame, easy to modify.

    Time wise, we estimate 3 hrs per joint.  That is both the mortise and the tenon of an adjoining member counting as one joint.  Also, that's timbers on the saw horses, the layout, joints cut, pre-fit, labeled, peg holes drilled, oiled, stacked, and banded for shipping.  I'm typically under the 3 hrs, but most people are typically over.  Another time estimation technique is to estimate a day per major timber, which is also going to get you in the ball park.  




Good luck with your project!

   
Thank you very much! Some great info there. :) 
Out of interest what oil do you use on your timber? 

trigger_andy

Quote from: Dave Shepard on March 19, 2020, 12:37:57 AM
If you are going to scarf, then you could go bigger. For just the four beams, I'd try to find a way to get the full length.

I've done the 12x16, and also a 16x20 version. I cut this 16x20 in 80 hours with hand tools, including boring all mortises with a hand crank boring machine and riving all the pegs. All peg holes were bored with an 18volt cordless drill.



Thats stunning! I really hope I can recreate something even remotely as good as that. :)
Obviously bigger is better, Id have more use for a 16x20 than a 12x16, would you recommend starting with a 12x16 first? Or would it not be that much different jumping right into a 16x20?
Any pics of them finished? Almost feels a shame to cover up all that lovely joinery. :D

Don P

I see you have a chainsaw mill, your length there is only limited by the trees.

Hilltop366

On a bandsaw mill for an extra few feet you can cut the maximum and let the rest of the log stick out, then slide the log down the mill and block up log level and cut the rest.

Or time for saw bed extension, with a two rail mill bed it would be fairly easy to add a temporary bed extension with wood beams and a bit of angle iron or more steel.

trigger_andy

Quote from: Don P on March 19, 2020, 07:59:25 AM
I see you have a chainsaw mill, your length there is only limited by the trees.
Which are mostly already cut to 15.5' for my softwood, or 9 foot for my Oak. :( 

trigger_andy

Quote from: Hilltop366 on March 19, 2020, 09:46:28 AM
On a bandsaw mill for an extra few feet you can cut the maximum and let the rest of the log stick out, then slide the log down the mill and block up log level and cut the rest.

Or time for saw bed extension, with a two rail mill bed it would be fairly easy to add a temporary bed extension with wood beams and a bit of angle iron or more steel.
Both good points. :)  The Mills now on a Trailer and not really posible to add extensions.
I'm happy enough to work with the limitations I have just now. Its really so I can get a feel for building Timber Frames and to learn. :) 

Dave Shepard

Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

trigger_andy

Thats stunning! I love the Barn Doors on the side. Or are they windows? 

Dave Shepard

They are doors. There are supposed to be windows over them also, but this was the day before the wedding, so just happy to have gotten this far. 
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

trigger_andy

I love it! Any pics from inside? 

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