the Carpentry Way: Gateway (83)                                                          

Gateway (83)

Post 83 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.


The second of three installments describing the gate's installation at site. Previous post.

April 1st ended with the main frame assembly (main posts, magusa, kabuki, and nose pieces) all set and ready to go with the main doors also mounted. Many blankets covered the pile and our hope was that upon return the following morning we wouldn't find someone sleeping underneath. The rear posts were positioned on their plinths.

April 2nd.

Originally the crane was scheduled for 7:30 am, however there turned out to be a couple of other tasks for which it was needed on the other side of the Museum, so it in fact rolled in at 9:30 am. That was fine, as it gave us a little more time to set up. It was nice to have a certain easing of pressure. We started by removing the main doors and re-stacking them with padding.

One thing to get ready were the stretchers, nuki, connecting the rear posts to the front posts. Matt J helped me out with this work:

I should mention that Matt J, who also helped during the foundation work on this project last year, works for a collective of sorts called Byggmeister, specializing in remodeling and energy efficient retrofits in the greater Boston area. I learn a lot from him about recent advances in technology in that area. I met him a few years back when he attended a workshop I taught in Japanese joinery.

The nuki required a bit of persuasion to slide through the post mortises, nothing too strenuous, and after they were in we could set the rear posts back up again, using a pair of sawhorses and beams as temporary support:

 All ready for the crane now, hardhats and all:

I'm a little nervous at this point, and more than a little fatigued, both mentally and physically. Hard to give a real smile in such a situation.

The crane rolled in and set up:

As mentioned in yesterday's post, I had rigged the frame assembly for the lift in such a way as to minimize any chance that the lifting straps could damage the stainless strips for the kabuki's copper roof cap. The crane operator, Ken, looked at it and said the rigging approach might not result in a plumb hang of the assembly after the lift. We could give it a lift though to see how things looked.

Several people had now rolled into the scene. A security guy or two came in to control pedestrian traffic, and a few photographers also, cameras dangling. The MFA's project coordinator was there. One photographer was from the Boston Herald, one was from the Boston Globe, and another from the MFA. It was exciting to have photographers there, in one sense, terrifying in another.

The Boston Globe photographer, Lane Turner, snapped the following picture upon our initial lift:

Image from: Getty images (link)

So, that wasn't going to fly - the posts were too tilted for installing. So, we set the unit back down again and re-did the slings, configuring them as chokes. We tried a second lift, which then required a slight tweaking of the slings, and then had another go. This time we had it hanging more or less plumb. Nowhere to go but up, up, and away:

That was something to see. My wife took all the video by the way. The professional photographers had to get in there as the gate got close to touchdown, so the last few moments of the lift could not be captured on film.

Funny enough, I wasn't especially nervous about lifting the assembly, which I had worked many months upon, up so high. While I have seen my share of harrowing crane disaster videos on Youtube, the lifting conditions here were entirely safe, the operator was experienced at working for the MFA, and the slings were brand new and several multiples stronger then the load they would bear. Fact is, if the slings failed with the gate a few feet off the ground, the assembly would likely be ruined, and putting it 100 feet or so into the air was not going to change that.

What I was a little nervous about was the mounting and connection onto the foundation and to the stretchers. While I had fit the stretchers individually to both the main posts and rear posts in the shop, I had never set up the entire assembly in my shop (due to a lack of space and lifting equipment) to check that the whole works went together. Remember, complicating things is that the rear posts are spaced further apart than the mains, are parallelogram shaped (as are the upper stretchers), and if there was any mistake in the angling of the mortises, or appreciable differences in heights of the foundation points, etc., there could be issues. That there could be issues, and some of them might be disastrous, was one thing giving me pause. On many jobs, you bring the cut assembly from the shop and install it to field conditions, the fitting often requiring a couple of tries and adjustments. Here, I had been the one to set the granite (last summer), so I had some control over the resulting precision of that install. Still, it is almost to be expected that there be some sort of hitch or glitch.

Adding to my anxiety was that there were a battery of photographers and other people taking video while the assembly was being fitted for the first time. What if it came down into place and something was out of whack, and we had to pull it off again? That might look like the dreaded 'something was wrong'. Partly I was nervous about looking bad in such a public manner (I could imagine the news headline and accompanying pics), partly I feared that something might be sufficiently out of whack that the assembly could not in fact be fitted. That was worst case, and though I generally thought it an unlikely outcome, however it was flickering across the back of my mind as a possibility.

Anyway, things went about as well as they could possibly go. The main posts came down exactly as planned:

And the stretchers fit as intended. Setting the right lower stretcher first:

I can't tell you how odd it is to be a bit stressed out by the whole process and not totally sure how it all will be coming together, and meanwhile in the background you hear the whirr of motor drives and the repeated 'clicks' of several cameras with every move:

Putting a ratchet strap on between the front posts and rear support posts as a temporary measure:

Again, Mike (in red) and Matt were such big help to me during this process.

Surveying the situation...

Everything was looking copacetic, so it was time to remove the straps and say goodbye to the crane:

Here, I'm chatting a little with the photographers, and hoping that their notes and observations, when they come into print, are reflecting the project in a way that is similar to how I perceive it:

I was so relieved everything had just fit perfectly! It was one of those moments in life I'll always remember.

Tightening down one of the nuts onto the 1-1/8" stainless threaded rods:

A look at one of the main post corners showing the copper protection and bronze hinge components:

With the gate's main frame locked down and in good alignment, I thought the next task should be to get the main doors on there. The sooner they were hung the sooner they were out of the way, and therefore no longer needing as much attention in terms of protection or secure storage. One issue stood in the way however.

A primary change I had made in the new gate from the old was in the foundation system. The old gate used welded metal 'shoes' to support the structure, and the posts themselves went down below the granite pavers. As a consequence, the bottoms of the posts had thoroughly rotted out. The new gate I designed employs granite plinths and sills to keep the wood several inches away from the soil, and all the post plinths were slightly larger pads than the post sections which were to sit upon them. It's logical that a support pad have a larger footprint than the part it supports, generally speaking, and having an offset in size masks any discrepancies that might result from the wood swelling or shrinking relative to the stone.

The doors hang, as is traditional practice with these structures, not within a frame but outside of it and the hinge stile's inner arris more or less meets the nearby post's arris. Since the door stile extends down below the bottom of the post, you end up with a corner of the plinth which interferes with the door stile - indicated by the black marked lines in this pic:

Now, there were several ways to potentially solve this issue. One could have narrowed the spacing between the main posts so that the post corners could be aligned tight to the plinth corner. However the problem with that is then you end up with an uneven reveal around the plinth. The plinth could have been made so as to be the same size as the post section, however that is both structurally a little illogical, and would have banked upon the post sections ending up exactly at target dimension, which, as regular readers of this blog will know, was certainly not a given with the somewhat unpredictable results obtained through the saw-milling and wood drying processes many months ago. The posts did actually end up about 1/8" under target dimension for width and thickness.

It may seem as well that it would be expedient to simply remove a portion of the door stile so that it would clear the plinth corner. That might have been possible were it not for one crucial fact, and that it that the doors to this gate are normally in the open position, and thus those adjustments to the stiles would have been clear to view and have looked a bit odd.

So, that left the best solution as one which seemed on its face to be difficult to achieve: cutting a rebate in the granite to clear the door stile. As I was aware of this issue many months ago, I had come up with an idea as to how to tackle this problem, and then I made some calls to various granite fabricators to ask them what they thought of my potential solution. They said they thought it would work. I did too, but wasn't 100% confident about it as I am not a granite fabricator. Mike and Matt were skeptical, giving me the raised eyebrow and all, and that's okay, I'm used to that.

My approach to cutting the rebate was to slice down both sides and across the bottom corner using a diamond tipped saw blade in a water-cooled circular saw. I picked up a Makita 4101RH for this, a 4.5" saw. It had good on-line reviews, people only complaining about the price, and I have generally been pleased with most Makita products. After the slicing, my idea was to break off the waste and chip any chunks out, and then clean up using a diamond coated router bit. I obtained the router bits from a specialist stone masonry company up in Vermont.

I figured these tools would get the job done, however having no experience with them, wasn't sure exactly how onerous the task was going to be. As it turned out, it was like slicing up butter -I couldn't believe how easy it went:

I was really happy to get through that without any hassles!

With those rebates cut, it was time to hang the doors, however the wind had really picked up. Given that the doors are rather large and heavy, it seemed prudent to put off the door hanging until a later time. So we moved onto other things - I'll be back tomorrow with another post to describe all that. Thanks for coming by the Carpentry Way. Next up is post 84.