Japanese Scarf Joint

[Brian_Weekley]

Check out this scarf joint.  Nice craftsmanship:

http://www.youtube.com/watch?v=W1pvUlQgYtk&feature=youtube_gdata_player

[tule peak timber]

Superb ....is an understatement. I look at that video and it gets me thinking. Thanks for posting . Rob

[Dave Shepard]

I think I saw a gap! :D

[Brian_Weekley]

It almost looks like they purposely left a gap to drive in a wedge to take it apart?

[Dave Shepard]

I'm guessing any gap they left was on purpose. I wonder if the extra time of doing that joint is rewarded by extra strength over a simple edge-halved and pegged joint? I think there is a lot about Japanese timber framing that is based more on tradition than actual mechanics.

[SwampDonkey]

There's a lot of old complicated joints in Japan and Europe that have out lasted most modern homes. Of course, in the end,  it all boiled down to how the wood is protected from the elements.  ;D

[John S]

Wow!!!

[terrifictimbersllc]

Inspiring.  Beats some of the joints in your barn, Brian,  but I can say firsthand not by more than 1/32 or 1/16 at most!   :D :D

I saw that gap too, thinking uneasily that they're not perfect, but then don't they use it to take it apart again.   Very careful not to ding any of that soft wood.  I'm sure those beams were harvested, sawn and worked with great reverence throughout and it shows.

[Ocklawahaboy]

I was pretty impressed that 2 guys could life the whole thing. 
I bet those type of joints hold up really well in the earthquakes they have over there.  Seems it would be able to move in all directions without breaking or turning loose.

[sawmilllawyer]

Fantastic work. Looks like a joint that would out last most of us here. Beautiful work, the accuracy is truly amazing!!!

[Magicman]

That joint is crazy pretty.   8)

[giant splinter]

Incredible workmanship, the guy with the sushi-head band is a little shakey at holding a hammer ( two near misses )  ;D but he did miss the beam. Very nice Brian ..... Thanks for sharing!





Mahalo

[D L Bahler]

Very nice joint. I am tempted to adopt this

[canopy]

A while back there was a thread about a workshop where scarf joints were tested for strength. For a future note on such exercises, it sure would be nice to see various Japanese joinery tested additionally. Their joinery looks incredible and it would be interesting to quantify if and how much the extra work equates to more strength.

[John S]

I have never cut a scarf joint but may have to in the near future (cheaper than purchasing a 12 foot extension).  From you guys who have cut them, what are your recommendations?

[Dave Shepard]

The type of joint will vary depending on the application. I have cut many, like maybe three or four dozen different scarfs. Most were post repairs, so they are a little different then something you might use on a long plate. There are many scarf joints in Jack Sobon's Historic American Timber Joinery.

[Heartwood]

My take on how to choose scarfs:
Splayed scarfs where there's significant shear stress. Halved otherwise.
Undersquint where you need to resist twisting.
Wedged scarfs for joints in tension (tie beams).
Bridled scarfs to resist outward bending (plates).
Bladed scarfs to resist downward bending.