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Planning a Japanese inspired garden shed

Started by GRadice, February 13, 2021, 05:37:35 PM

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JRWoodchuck

What is the purpose of the kerf cut on the male portion of the joint? I see it wraps the knot so it looks specifically placed. 
Home built bandsaw mill still trying find the owners manual!

GRadice

Ah. It's not a kerf, just a shallow check that happened to run along the tenon.
Gary

GRadice

I have the peripheral floor beams done and am on to the two sleeper beams (obiki 尾引). Shown from below they are the two beams colored tan.



 

As you can see one of the sleepers is part of the three-beams-to-post joint and the other connects directly to two peripheral beams. They span 6 feet and are 130 mm x 110 mm, roughly 5" x4". The sleeper that joins in the post has a tenon notched to capture the long tenon of the peripheral beam. The notch is displaced 1 mm toward the sleeper shoulder to give a slight draw bore effect that pulls the sleeper tighter to its post.

The other sleeper is joined to the peripheral beam with a partially housed double tenon. This joint is subtle. It maximizes the strength of the sleeper without removing too much wood from the peripheral beam. It also resists twisting. Often these sleepers are supported in their centers by posts underneath. I don't think I need them in my case but I can add them. The sleepers are also notched for cogged lap joints with the floor joists. The cogged laps eliminate the need for blocking to prevent the joists from rolling over or twisting.

One final design to note is that the sleepers are offset downwards 30 mm from the peripheral beams to accommodate the elevation of the joists in their cogged laps.



 



Gary

GRadice

Got the sleepers all cleaned up and moved on to the side floor beams. Those have pockets on their inner faces to support the ends of the floor joists. I chopped the pockets out on both side beams and then laid those beams and the sleepers side by side to admire my work:



 

Oops.

After picking myself and dusting myself off I figured out how I made that layout error (I won't bore you with it, just a dumb mistake) and decided my goof on that one side beam wasn't a catastrophe. I just need to even up the widths of those laps and pockets making them 52 mm instead of 48 mm wide. I haven't milled the joists yet and my stock is 60 mm wide so I have room to play. And nothing wrong with having marginally stiffer joists at slightly more than 2" wide rather than slightly less than 2".

Here they are almost all adjusted.



 

If I'm lucky this will be the worst mistake I make.
Gary

JRWoodchuck

Really excited to see this get put together!
Home built bandsaw mill still trying find the owners manual!

GRadice

Quote from: JRWoodchuck on September 27, 2022, 05:15:38 PM
Really excited to see this get put together!
Me too, but man it's still going to be a while. I was hoping to get it raised and roofed before the Willamette Valley rainy season begins again but prospects are looking dim. Plan B is to get the frame cut and store it over the winter while I work on the doors and windows and gable end lattices. Not the best idea to cut joints and let it sit because wood will move. But the wood is also dry now, not green, so maybe it won't move too much.
I see you are in Baker City. My wife and I were there in June on our way back from Yellowstone. Stayed at the very cool Geiser Grand Hotel and took a lovely early morning dog walk around downtown admiring the fascinating architecture. An Oregon small town gem.
Gary

aigheadish

Could you fill the joints with scrap over the winter or that wouldn't stop it from moving enough to worry about? Maybe some extremely hard wood to keep things more still? (I have no idea if that possible, I don't really know what I'm talking about, just fascinated with this project)
New Holland LB75b, Husqvarna 455 Rancher, Husqvarna GTH52XLS, Hammerhead 250, Honda VTX1300 for now and probably for sale (let me know if you are interested!)

GRadice

Quote from: aigheadish on September 28, 2022, 06:52:12 AM
Could you fill the joints with scrap over the winter or that wouldn't stop it from moving enough to worry about?
That's an interesting idea. After thinking about, I guess I'm more concerned with the beams twisting or bowing and throwing the joints out of alignment than I am about the joint components shrinking or swelling. But, not much I can do about that. Perhaps do some partial assemblies?
I finished the joinery for one of the eave beams. For scale it is 13 ft long. The notches are for rafters on 1 ft centers. The ends have a mortise for a floating rod tenon that will join the barge boards to the eave beam.


 


 

 
Gary

aigheadish

Duh, yeah, the whole beams moving makes more sense than the joints closing up on you...
New Holland LB75b, Husqvarna 455 Rancher, Husqvarna GTH52XLS, Hammerhead 250, Honda VTX1300 for now and probably for sale (let me know if you are interested!)

JRWoodchuck

Glad you had a nice stop over. Pretty fortunate to have grown up here and get to raise my family here! Could you put it together in bents? Just for storage to keep things together? Although I can't imagine being dried to 11-12% they'll move to much...
Home built bandsaw mill still trying find the owners manual!

GRadice

Yes maybe do some partial assemblies. I have a 10x10 canopy set up outside that would mostly cover the bent equivalents during the winter rains. That would also give me more space in the shop for making the doors and windows and gable lattices over the winter.

I finished the other eave beam. Next up is the ridge beam sitting there on the right.



 
Gary

GRadice

I finished squaring the ridge beam and backing it for the rafters.





Then layed out the mortises for the rafter ends. Sato and Nakahara's book has three approaches for framing rafters to ridge beams. I chose the second method since my rafters will be exposed and the pockets/mortises help resist twisting of the rafters.





 



Gary

GRadice

Barge boards to ridge beam.


I'm using this joinery to attach the barge boards to each other at their miter. These are test boards to make sure I got the layout right. The tapered key will draw the boards in tight but I didn't tap it all the way in since if you do that, good luck getting it back out.



 

 

 

 

Then worked out the joinery that fixes the barge boards to the end of the ridge beam. It will be a loose tenon with a sliding dovetail in a slot on the barge board, and a horizontal stub tenon.



 



 
Gary

GRadice

I took a small break from the shed to make a Japanese style birdhouse for a friend. I've done a couple of these before, he liked them, and I bartered in exchange for some black locust boards he has, that I'd like to use for pegs and wedges in my frame. So this really is part of my shed build.

The bird house has Port Orford cedar frame parts and panels with black locust barge boards and Osage orange ridge cap. Mostly joined with timber framing joints plus a couple of screws and some brass bits for the door.



 



 



 

 



Gary

JRWoodchuck

Home built bandsaw mill still trying find the owners manual!

GRadice

Back to the shed. I have sawn, chiseled, and routered most of the rafter pockets on the ridge beam. I made a rafter template to check the angles and dimensions of the pockets. New shop dog is not impressed. That hurts my feelings but she's cute so I'll let it go.



 

 
Gary

realzed

Great looking birdhouse!
Willa looks like she would prefer you spending the time going for walks with her though..
She is getting big fast - and yes still cute! 

GRadice

The three King posts done. All of 18 inches shoulder to shoulder. The other shop dog, Stella, says, "big deal". I thought dogs were supposed to adore us?

I laid out the tools I used to lay out and cut the tenons and square up the shoulders and cheeks. The 330 mm ryouba saw did most of the work. The little rectangular block is also a tool used to check the shoulders and cheeks for square and flat. Basically a gauge/gage block. Very handy.







  
Gary

btulloh

Those planes with the angled irons look interesting. Not familiar with angled irons. I use a couple Japanese style planes, but hadn't seen angled irons before. 
HM126

GRadice

Those are skewed rabbet planes, called kiwaganna. They are tricky to set up since the blade angle can't be adjusted except by sharpening. But boy are they handy for adjusting tenons and shoulders.
Gary

GRadice

Got one of the stepped tenons on one post finished. Not my best work but OK I think. It took some trial and error to figure out a method to cut the long rips. I eventually settled on slanting the post on a saw horse for most of the cut, flipping the post occasionally. With a pull saw, holding the sawing line on a rip cut is easier when cutting uphill against the grain because the far end of the saw is guided by the existing kerf. Although the saw does tend to catch more often than cutting downhill.

I have a template of the mortises to check the fit.



 

 

 

Gary

GRadice

I finally finished all of the stepped tenons.



 
Gary

GRadice

I have almost finished the horizontal bracing beams known as nuki. These are generally dimensioned a little thinner and not quite as wide as a 2x6 (30 mm x 130 mm in my case). They are typically joined with a wedged half dovetail at end posts, and with a wedged cogged lap in intermediate posts. The are spaced on about two foot centers. In traditional construction there are no knee braces although in modern construction diagonal bracing is often required by earthquake codes.



 



 

This is how the half dovetail looks after it is wedged in place (in a test sample).



 

This joint is common in Japanese carpentry and has advantages over a pegged mortise and tenon.

1. Under tension, the joint becomes stronger because the half dovetail wedges and compresses against the long grain of the post. The greater the tension, the greater the wedging and the greater the resistance to pulling out. It doesn't rely on a relatively skinny peg or a long relish for strength.
2. No part of the tenon is exposed and no peg is exposed to weather.
3. There are no shoulders to cut, simplifying the joinery and fit.
4. If the joint is left exposed the wedge can be tightened if the joint opens up because of shrinkage. Although, usually this would be done with dry timbers and hidden inside a plastered wall.

 





Gary

JRWoodchuck

Gary curious who made your Kiwas? I bought one a few years ago and would like to replace it with a pair at some point the blade on mine likes to chip. I've bought most of my stuff off eBay and am getting to the point I'd rather spend more money to get higher quality than hope I'm getting something decent. Also did you study in Japan? Your knowledge seems to be to deep to have learned off YouTube. 
Home built bandsaw mill still trying find the owners manual!

GRadice

The kiwaganna are made by Hideki Komori and I got them from Stan Covington. I get most of my Japanese tools from Stan since I know I can trust his advice. He also enthusiastically walks you through set-up of whatever you buy. His tools are not cheap, though.


https://covingtonandsons.com/2021/11/13/japanese-handplanes-the-kiwaganna-skewed-rabbet-plane/

https://yoita-uchihamono.com/global/craftsman/komori/

I have a few tools I've bought from auction and saved some money, but the downside is unless you read Japanese it is hard to know the names of the makers, and harder then to know which makers are good. And most used tools need a fair amount of fettling so you have to know how to do that.

No, never studied in Japan. But lots of diligent study here: reading everything I can find, watching videos, and asking questions of folks who know way more than I do. For joinery, the most valuable sources I've found are the blog and monographs by the late Chris Hall (The Carpentry Way), and a couple of books in Japanese that I can't read but the illustrations are superb. For carpentry, there are a handful of books in English, and I'm fortunate to get advice from Dale Brotherton who builds Japanese style structures in Seattle.



Gary

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