the Carpentry Way: Gateway (47)                                                          

Gateway (47)

Post 47 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.


A balmy -4˚C in the shop today. Feeling a little under the weather, so I didn't tend to stray too far from the portable heater. Problem is, the heater just about maxes out the available amperage draw on the circuit, so if i use the sliding chop saw, or the bandsaw, the breaker trips and has to be reset. A little tedious after a while.

Started with the finishing up of the rod mortises on the two headers:

Earlier, I managed to stick myself in the thumb with the corner of the chisel, hence the bandaid. Clean cuts heal quickly at least.

The headers were completed with some trimming and chamfering.

Then on to today's layout and cut out task: the mud sill, or dodai:

The mud sill on the original gate sat in/on the ground, so by the time I pulled it out after 25 years it was mostly soil itself. The new gate features a granite foundation bringing the wooden parts well away from the ground, however I decided to place the mud sill timber into limited contact with the granite, preferring to give the wood as much air circulation as possible on its under surface. So, I designed it with a couple of scallops removed from the underside, leaving only the middle 10" or so to bear on the granite. This gives the best compromise between carrying the modest load of the panels above, and letting air circulate below. It's a bit non-standard, however I think these minor modifications will extend the lifespan of the piece quite a bit. It is the only horizontal structural member in close proximity to the ground, so I considered the matter carefully at the design stage.

The cut out occupied most of today, and I managed to complete the work on the mud sill by the end. Here are the three parts, mud sill on the left and then the two headers:

The rightmost header is the one which is on the side door (right) side of the gate.

A closer look at the timber ends from the same vantage point as the previous photo:

The mud sill has a pair of hammerhead tenons on one end, which are captured by the wall post on that side.

The opposite ends of the same three sticks, this time the mud sill is of course on the right side of the photo:

On this end, the mud sill has the same sort of rod tenon attachment as the headers. The difference in the joints from one end of the mud sill to the other are accounted for by the fact that on the connecting wall post end, the wall post itself sits on a plinth about 1" higher than the granite sill under the mud sill and the connection is right on the bottom of the post, while on the flanking post side the mud sill connects a couple of inches up from the bottom of the flanking post. The differing configurations cause the joinery solutions to vary accordingly. In either case, the joinery is entirely concealed. While the rod mortise on the sill is oriented upwards, the top of the mud sill will be clad with a copper sheet to provide additional protection.

The mud sill will also have a dado to capture the lower ends of the infill panels, however I will leave this portion of the cut out for later on when it comes time to fit the panel assembly to the frame.

Next, a view showing the profile of the mud sill a little better:

I have a little bit of clean up to do yet on the relieved surface, and plan to paint those areas to dampen moisture exchange.

One more, a closer look at the three rod mortises:

That leaves me with two more components in the frame to lay out and cut out, namely the kasagi. I am waiting on some shaper tooling for some profiling work on those two sticks, however I intend to process the joinery tomorrow, and  mill some stock for the doors as well.

That is it for now- thanks for coming by. On to post 48.