Post 43 in an ongoing series describing the design and construction of a kabukimon, a type of Japanese gate. This is a project for the Museum of Fine Arts in Boston. Post 1 in this series can be found here if you'd like to start at the beginning. Each post links to the next at the bottom of the page. Recent installments also to be found in the 'Blog archive' index to the right of the page.
Most of today was consumed with the last step on the wall posts, namely cutting the end tenons. The tenon arrangement is a double hammerhead, occupying about half the top of the stick. These involved several steps to cut out, and it took a good while to complete.
I was trying hard to hit my marks today. The spacing and thickness of the necks on the tenons was the critical bit. If the head is slightly skinny, or short, or the head angle a hair out, it is no big deal. The necks however are the starting point in cut out for indexing the tenon spacing, so I took care to hit my numbers as closely as I could.
Tenon neck spacing was set at 4.00", outside to outside:
The other post came out similarly:
Tenon neck thickness was 1.00" - here's one tenon neck in the caliper jaws, a hair over dimension:
And on the other stick, I hit the same number:
And number 4:
The front surfaces of the tenons were decked a 1/4" and the cut out on the wall pasts was done:
I used a go/no go gauge to check the hammerhead shoulder offsets:
I find that with careful paring with a sharp chisel, you can pare a surface to a +/- 0.003" without too much trouble - - so long as you can measure that accurately of course, and don't get too aggressive with the trimming. The tool needs to be reasonably sharp of course. The go/no go is 0.004" under target, which is of no consequence as I have yet to cut the mortises. I will want a slightly tighter dimension on the neck height on the tenon so that the joint draws down snugly when slid together.
All for today - next up on this project are the flanking posts, which I have already started in on. More tomorrow on that. On to post 44