The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: Brian_Weekley on February 06, 2015, 07:46:23 PM

Title: Japanese Scarf Joint
Post by: Brian_Weekley on February 06, 2015, 07:46:23 PM
Check out this scarf joint.  Nice craftsmanship:

http://www.youtube.com/watch?v=W1pvUlQgYtk&feature=youtube_gdata_player
Title: Re: Japanese Scarf Joint
Post by: tule peak timber on February 06, 2015, 07:54:57 PM
Superb ....is an understatement. I look at that video and it gets me thinking. Thanks for posting . Rob
Title: Re: Japanese Scarf Joint
Post by: Dave Shepard on February 06, 2015, 09:10:01 PM
I think I saw a gap! :D
Title: Re: Japanese Scarf Joint
Post by: Brian_Weekley on February 06, 2015, 09:19:39 PM
It almost looks like they purposely left a gap to drive in a wedge to take it apart?
Title: Re: Japanese Scarf Joint
Post by: Dave Shepard on February 06, 2015, 09:22:36 PM
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.
Title: Re: Japanese Scarf Joint
Post by: SwampDonkey on February 07, 2015, 05:35:32 AM
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
Title: Re: Japanese Scarf Joint
Post by: John S on February 07, 2015, 10:19:40 AM
Wow!!!
Title: Re: Japanese Scarf Joint
Post by: terrifictimbersllc on February 07, 2015, 06:18:23 PM
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.
Title: Re: Japanese Scarf Joint
Post by: Ocklawahaboy on February 07, 2015, 06:27:37 PM
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.
Title: Re: Japanese Scarf Joint
Post by: sawmilllawyer on February 08, 2015, 05:51:26 PM
Fantastic work. Looks like a joint that would out last most of us here. Beautiful work, the accuracy is truly amazing!!!
Title: Re: Japanese Scarf Joint
Post by: Magicman on February 09, 2015, 09:09:34 AM
That joint is crazy pretty.   8)
Title: Re: Japanese Scarf Joint
Post by: giant splinter on February 09, 2015, 10:07:28 AM
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
Title: Re: Japanese Scarf Joint
Post by: D L Bahler on February 09, 2015, 12:30:44 PM
Very nice joint. I am tempted to adopt this
Title: Re: Japanese Scarf Joint
Post by: canopy on February 09, 2015, 07:21:58 PM
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.
Title: Re: Japanese Scarf Joint
Post by: John S on February 11, 2015, 04:26:00 PM
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?
Title: Re: Japanese Scarf Joint
Post by: Dave Shepard on February 11, 2015, 04:35:55 PM
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.
Title: Re: Japanese Scarf Joint
Post by: Heartwood on February 11, 2015, 05:40:44 PM
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.