The Fuigo Joinery: Part IV

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Welcome back! I’m working again on the fuigo, a traditional Japanese wooden bellows.  They’re quite simple in design, but not commonly made by skilled woodworkers here in America, usually by blacksmiths and aspiring swordsmiths, so the joinery element can be a bit undeveloped. Don’t fear the joinery, its a question of durability, not just aesthetics. Its occurred to me more than once during this build how powerful a tool is the hand plane, kanna, that it can handle such large and wide material at such a moderate cost. I’m looking at planer/joiners right now and its not even worth my money to get a joiner smaller than eight inches. Because of my hand planes, I can afford to wait for the right beast of a machine to come my way. Who knows if it ever will?

The photo above is the tuyere bearing block with its hole cut, being used to mark the hole in the birdhouse side. I had meant for the tuyere bearing block to be a bit wider, but there was an error in my plans concerning the internal width of the piston box. I cut both the piston rod bearing block and the tuyere bearing block from the same length of stock, and had to switch them around to have a usable piece of wood after cutting the piston rod bearing block too short.

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If I was being super traditional about every detail I would be nailing these two pieces together. As it is, I find screws to be friendlier to the next person who’ll have to work on this. To keep the outside of the fuigo looking clean and unencumbered by a bunch of screws I hid as much as possible on the inside face.

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The piston rod bearing block was next. I clamped the block in position on the side. Previously I bored a pilot hole in the side where I wanted the piston rod to come through.

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With the proper position maintained by the clamps the side was removed and drilled from the back for screws to attach the bearing block. I also drilled through my piston rod locating hole so that it marked the bearing block.

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Boxwood anyone? This stuff is very dense, one of the better bearing woods after ironwood. I cut myself a small piece to inlay into the bearing block.

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Working on small pieces at the planing board can get difficult because there is not enough room to place your foot directly on the piece. I had to use my heal to hold it against the planing stop. This is probably the widest mortise I’ve ever chopped, full width of my 48mm chisel. I cleaned to depth with my router plane, though it was a little large for the blade to work in such a small space.

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With the mortise cut I used my shooting board to trim the boxwood bearing to a perfect snug fit against the end grain. Hopefully when this bearing shows too much wear, probably after I’m dead, the next guy will be able to pop the old bearing  out without any trouble and source a replacement.

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With the bearing installed I re-mounted the bearing block and centered the whole affair on the drill press table for a 1″ hole with a forstner bit. It is really, really important that you get a good straight hole here, so that the piston rod won’t jam and you maintain as tight a fit about the bearing as possible to minimize air leakage.

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And here it is, the finished bearing, cool! I had considered using a piece of steel pipe, or copper, brass, whatever. Compared to buying a brass bearing the nine dollars I paid for my little chunk of boxwood will make a LOT of different bearings. I’ve used wooden bearings on bobbin winders, spinning wheels, they’re awesome.

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With the bearing blocks finished I took apart most of the fuigo and installed the glass across the bottom and the piston stops. Notice the length of the piece of glass relative to the length of the fuigo. For a while I wondered why you would sacrifice the length of internal displacement and put a shorter length of glass in the fuigo than it could handle. The reason has to do with the piston rod bearing, and the tolerances that you can achieve. Just as with a spinning wheel’s bearings for the wheel, you want your bearing points to be as far apart as possible. By using a shorter length of glass and placing it as far toward the back as possible you insure that the bearing rod is less likely to bind in the fully pulled back position.

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Installed the flapper valves. This thing is starting to look like a proper machine!

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I reassembled the sides and found a stupid error. When I originally installed the birdhouse side to mark the  bevel on its top edge I tapped it in with a block and hammer. What I didn’t realize was that the tapping with a hammer caused the sides to pop up a little bit. Thus the birdhouse side was made too wide. I had to go back and plane it down, definitely an error I’ve learned from about assembling cabinetry. The birdhouse side was just a tight fit, to get it back out I had to tap on the bottom board like backing out a plane iron

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In any case it was an easy mistake to fix, and I soon had the birdhouse top installed with some screws through the face.

I finished the fuigo up yesterday, this post is just getting too long to show it all at once. I don’t have a tuyere pipe yet, I’ll definitely need to shoot some video of this thing breathing life to a fire once I get it set up. Stay tuned!

Oh, Sebastian just posted some drawings by Mark Grable for an Open Source Forge. Really beautiful work Mark, inspiring and at just the right time, thank you.

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