Joint No. 2: Koshikake Kamatsugi (Stepped Gooseneck Splice)

Were back at it again! This is joint no. 2 for our series Project Mayhem. As always, if you’re reading this feel free to join in and we can learn together. The rules are here, but to recap a la Sebastian:

No electric tools.

Document the process.

Document the tools used.

Time it.

Discuss it.

Blog it.

I knew I wanted to do a scarf joint, I just didn’t realize how awesomely complicated they can get in execution. I thought the gooseneck splice was complicated, but its unfortunately one of the simpler ones, and builds on the layout and execution skills developed in the previous exercise. So here we go…


I have tried to provide some simple ratios to help proportion the joint.


This is a great joint for connecting groundsill beams together when you’re building your dreamy timber frame shop.

Gentlemen, there are seven days from today.

Finish by June 30, 2015


5 thoughts on “Joint No. 2: Koshikake Kamatsugi (Stepped Gooseneck Splice)”

  1. Very nice choice Gabe!

    The addition of the proportions is greatly appreciated, I might just end to with a joint that looks the way that it is supposed to, haha.

    I’m in!

    1. Nice work Wilbur, I really enjoyed reading your post. The book that I have for referencing this is “Wood Joints in Classical Japanese Architecture” by Sumiyoshi, Matsui. They do not show the taper on the back of the gooseneck and related taper on the mating female piece that help to pull this joint together. It makes this joint more interesting, does it not? I’ll have to incorporate it when I try my hand at this one.

    1. It would be oriented horizontally to the ground, for splicing groundsills (sill plates). The book I have says its meant for square cross section lumber 150mm to 200mm in size. Above that and you’re looking at using an oblique rabbited splice. Give it a shot?

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