Stepped Gooseneck Splice (Koshikake Kamatsugi)

Here's another Japanese architectural joint for you to try.

The Stepped Gooseneck Splice is used in groundsills to join sections.

The video might help you assimilate the written instructions better.

Square the sections to be joined

Mark the length of the joint to be about 1½ times the section width

Mark in the 'neck' width, and gauge it to the end

Measure for dovetail shoulders at the halfway point

Mark in the shoulders, and join up the head of the gooseneck

Mark the waste material

(Use the proportions in the photo's to size the joint to your work)

Square in the verticals

Add a step half way down the sides

Mark all the waste areas

Knife in all the lines to cut

Saw the lower half away, below the dovetail head (I've left the step portion remaining for the time being, but you don't need to)

Saw down the sloped sides of the dovetail head, and continue to the main joint shoulder line, before sawing the waste away to the shoulder line

Saw the shoulders of the dovetail head, and then pare away the waste to reveal the straight neck

The final photo shows me removing the step portion

Place the male part in position above the other section, and mark around it.

Knifing the outline should improve accuracy

Mark in the waste, then transfer the step down to the halfway point, gauging round a line

Saw down the neck lines, until the blade reaches the edges of the marked in waste

Now use chisels to chop and pare away the gooseneck socket

Finally saw off the step section

Test the fit - don't force it, since you will find it impossible to remove, if it jams, without damaging it

Make any adjustments for a good fit

In a groundsill application, gravity, together with the structure built upon it, should hold the parts together

In other applications, apply glue to the socket before assembly

That's all there is to it!

I hope you enjoyed my Instructable. Follow to see more stuff like this.

Cheers,

Mitch