Editor’s note: Due to extensive work on “The Stick Chair Book,” it’s been a little while since we published a chair chat, today we are back with a Swedish chair assembled with Fish Glue and primitive IKEA joints. Salty language about pizza, electrocuted meatballs and potatoes will follow so be warned. For those who are easily offended, here is a video with a dog on a plane instead.
(more…)Author: fitz
Woodworker, writer, editor, teacher, ailurophile, Shakespearean. Will write for air-dried walnut.
‘Making & Using Punches’
The following is excerpted from “Joiner’s Work,” by Peter Follansbee – in effect a doctoral thesis on processing furniture-shaped chunks of lumber from the tree using and axe, froe, hatchet and brake. Follansbee dives into deep detail on how he festoons his pieces with carvings that appear complex but are remarkably straightforward – plus lessons in 17th-century casework. His approach to the work, which is based on examining original pieces and endless shop experimentation, is a liberating and honest foil to the world of micrometers and precision routing.
The book features six projects, starting with a simple box with a hinged lid. Follansbee then shows how to add a drawer to the box, then a slanted lid for writing. He then plunges into the world of joined chests and their many variations, including those with a paneled lid and those with drawers below. And he finishes up with a fantastic little bookstand.
Punched accents often enhance carved decoration throughout the design. These punches are sometimes just a textured effect, often called “stippling,” in the background, or extended to include stars, crosses, floral patterns and other designs stamped onto the solid foreground of the carvings.
Here’s my main set of punches (Fig. 3.41). From right to left, a 5/32″ nail set, a Maltese cross filed from a large cut nail, a background punch, and a small flower design. All but the nail set are shop-made.
Working metal is one of my least-favorite shop tasks, but I can usually worry my way through making some punches. It only takes a few minutes. The stock is usually pretty soft; the hardest stuff I file is when I use an old cut nail. I have no hack saw, but one would be handy if you’re going to do much of this work. One place it would help would be trimming the length of something like the cut nails if their point is too small a cross-section for the intended design. Otherwise, a grinder of some sort, or some coarse filing brings the end down to a clean and finished blank.
I start the background punch with a piece of stock about 1/4″ x 1/2″ x 3″ long. Make friends with a blacksmith; they have this stuff around. I file a row of lines dividing the punch across the wide dimension (Fig. 3.42). First in half, then half again etc. I use a feather-edge file to start these lines; you could use the hacksaw first.
I angle the feather-edge file by tilting the handle down to start this line. Then I gradually bring the handle up, lowering the file into the cut. I think of this as scoring the lines. I’ll finish them with a triangular file.
Then flip the piece in the vise, and file a couple of lines to define the other rows (Fig. 3.43). In this example, I filed two lines one way, and four the other, creating a punch with three rows of five teeth.
Don’t worry if your lines aren’t perfectly parallel. Get them close and then you’ll work on making things even out with the next filing.
Once I’ve defined the layout with the feather-edge file, I switch to a triangular file to bring the teeth of the punch down to size (Fig. 3.44). Drop the triangular file into one of your slots you just made, and start to work it along. Check your progress frequently – things can change shape quickly. I find I have to tilt my point of view this way and that to catch the teeth in the right light. Aim for small “heads” to the punch’s teeth, evenly sized. Evenly spaced is good, but not as big a deal as size. If some teeth are too big, they won’t make as deep an impression.
The triangular file is easy to guide. Keep the top surface of the file level and the other two sides will be symmetrically aligned as they work mating sides of the row.
Variation in tooth size is expected, but teeth that are too big keep the punch from working well. The outer rows on this punch are both too big, especially the one on the right (Fig. 3.45). This is easy to fix. There wasn’t enough room to file another row, so I beveled off the outer corner of the punch, until I brought those teeth down to size.
Periodically take the punch from the vise and strike it in a piece of scrap wood. It’s good to be organized so you can keep track of your progress. I wish I were.
Make the accent punches in a similar manner. For the round flower punch I angle the feather-edge file so it’s just hitting at the corner of the punch’s end (Fig. 3.46). I file a notch from the outer edge to the middle, then turn the punch in the vise and file another notch across from the first.
Tilt the file to come across the end of the punch. Sometimes you have to then tilt your head so you can see where you’re going. File a little, look a lot.
Keep splitting the spaces in half as best you can. If it gets off-kilter, split any thicker spaces in half again.
At this point, my pattern is out of whack (Fig. 3.47). What’s more important than symmetry is that the remaining “petals” are narrow. The wide parts in this view got filed to split them into smaller bits.
It’s surprising how small the remaining parts are to make the pattern work. It’s mostly negative spaces in the metal to create the impression in the wood.
Some find and use leather punches; I have no experience with them. If they are large enough they should work fine. If the business end of them is too fine, they might not make an actual impression in the wood. An easy way to see if a punch will work is to smack it on various pieces of scrap wood. Lightly on softer woods, harder on hard woods.
Covington Mechanical Library Shelves
EDIT: I added my SketchUp model of the shelves to the 3D Warehouse. You can download it here. —CS
Continuing in our tour of simple fixtures in the Lost Art Press shop (last week, I posted the tool walls), above is a picture of the wall o’ books in what we call the Covington Mechanical Library.
These are pieces of screwed-together 2×12 (which start off at 1-1/2″ thick, and have been planed until pretty). If I recall correctly, there are three, maybe four, screws into the top and bottom of each upright, through the horizontal pieces, all sitting on a screwed-together base. The shelves are secured to the wall with many L-brackets that are bolted to the masonry wall. A lot of visitors bring their children to the storefront, so we wanted to make sure the unit could be safely scaled by a gorilla.
And while they looked ridiculously capacious when Brendan Gaffney finished constructing them from Christopher Schwarz’s drawing, they were full up with woodworking tomes in just an hour or so.
The drawing below – plus knowing that the pieces are from 2x12s – should provide enough detail for you to easily adapt such a system to your own library wall needs.
– Fitz
The Ubiquitous LAP Tool Walls
In many of the picture of the Lost Art Press shop our “tool walls” show up. They’re hard to avoid, given that they’re in back of Christopher Schwarz’s workbench, and take up half of the back wall of the shop. And every time they show up, we get questions about them – so here are some answers.
The walls are actually heavy wooden sleeves that fit over three “boarded bookcases” (from Chris’s “The Anarchist’s Design Book“), made from pieces of not-great cherry that we’d had for at least a decade.
The walls are simply enough pieces of 3/4″-thick (or thereabouts) cherry butted together (with a small gap – about a dime’s width) to make up the width of the bookcases (which are about 36″ wide), long enough so that they leave a small gap at the bottom (of about 1″) to allow access underneath to lift.
Clinch-nailed across the bottom on each wall is a piece of 3/4″ cherry, with another flush to the top; these hold the vertical boards in place. Glued and screwed to the back edge of the top is a panel that spans the top of the bookcase plus 3/4″ (3/4″ x 14-1/2″ x 36), with another piece (about 4″ wide) glued and screwed to it that sleeves over the back.
At the two front corners are two triangles (gussets?) screwed in place with (quelle horreur) Pozidriv (I think) screws. The ones on the sides are countersunk; the ones on the top are not. And I’m fairly certain the boards were used fresh out of the powered planer. In other words, these are pretty much slapped together out of available stock. And we finished them with two coats of shellac. But they hold a lot of tools and they look nice, as long as you don’t examine them too closely. We add a new nail or Shaker peg whenever a new tool needs a tool-wall home. Or we make a simple rack if that’s the best storage solution, and screw that to the wall.
Please note that only our non-personal tools live on these walls. If it’s hanging out in the open, it’s fair game for students, contractors, spouses… The stuff we don’t want people to use? Stashed in our tool chests.
I argued for some kind of hinged or sliding doors, so that the bookcases behind the tools would be easier to access, but I lost (so if I have to get into one of the bookcases, Chris has to help me – I can’t lift those myself…and Chris lifts them by himself only if absolutely necessary). For as often as we need to remove the walls, it was too much work/trouble. So, when we have an open house and need to access the bookcases (where we display the Lost Art Press books), we remove the tools from their various hooks, nails and pegs, lift the walls off the bookcases and stow them in the back, then hang the tools back on the walls until we’re ready to cover up the books again. Not only does this give us a place to store the shared tools, it protects the books from dust and workshop bruises.
And come Saturday, Aug. 7, 2021, we’ll be lifting off all three walls for the first time since December 2019 if memory serves – from 10 a.m.-5 p.m. that day will be our first open house in more than a year, and we hope to see you here!
– Fitz
Drying Wood Using Air
Richard Jones has spent his entire life as a professional woodworker and has dedicated himself to researching the technical details of wood in great depth, this material being the woodworker’s most important resource. The result is “Cut & Dried: A Woodworker’s Guide to Timber Technology” (from which the information below is an excerpt). In this book, Richard explores every aspect of the tree and its wood, from how it grows to how it is then cut, dried and delivered to your workshop.
In section 6.4 the drying and rewetting of wood was illustrated by using a sponge or towel to represent wood. An extension of this analogy serves as a preliminary introduction to terminology about the wood-seasoning process.
Let’s say, for the sake of discussion, that you soak a very large and thick bath towel in a water bath. Lift up the sopping towel and wring it out as thoroughly as possible. Let us also assume you have the unlikely physical ability to wring out every drop of loose (free) water in the towel so the only water left is that bound within its fibres. This towel now stands for wood commonly and erroneously described as being at fibre saturation point (FSP), although the comments on FSP made in section 6.5 should be borne in mind. Fold the towel up three or four times into a long large sausage and hang it over a washing line. It’s a cool, dull, still, overcast day with, perhaps, intermittent, very light drizzle.
The towel will barely dry any further in the described weather conditions until either a breeze starts, the sun comes out or both changes happen together. It’s common knowledge that even if the sun doesn’t come out but a breeze starts the bundled-up towel will dry. Similarly, if there’s no breeze but the sun comes out the additional warmth causes water to evaporate from the towel’s fibres. In both cases described, the towel will eventually dry through. Put the two factors together, i.e., warmth and moving air, and the towel dries more rapidly than it will with either just a breeze or just extra warmth. Within the bundled-up drying towel there is a moisture gradient: As the towel dries it remains wetter in the middle of the bundle than near the surface. Assuming drying continues, the moisture content within the towel gradually evens out until it has an equal moisture content all through.
Without really knowing any science or terminology we know how to dry clothes quickly. Options include hanging them on a washing line on a warm, lightly breezy, sunny day, putting them out on a dull but dry and windy day, or hanging them over a warm radiator, and so on. Clothes fully opened and pegged on a line dry much quicker than clothes bunched up tightly.
What applies to drying clothes has similarities to the conditions that will dry wood. To dry wood quicker, heat air and move the hot air over it, although with wood, when it has dried to approximately 20 percent MC, the primary drivers for further drying are air temperature and humidity, not the speed at which the air passes over the wood. Thin boards dry faster than thick boards, which is analogous to opening clothes out to dry rather than leaving them bunched up. Fast drying of wood with very hot dry air will certainly accomplish the task, but it usually comes with an unacceptable price, i.e., degradation of one sort or another such as splitting, surface checking, case-hardening18, collapse (aka core collapse), honeycombing etc., making the wood unusable and unsellable. It’s imperative to control the speed at which wood dries in order to produce an acceptable end product.
The air’s RH must be low enough to absorb more water vapour. Air at 100 percent RH cannot absorb any more water vapour. Wet wood in RH conditions like this is comparable to my earlier description of hanging washing out to dry on a cool, damp, intermittently drizzly day – the clothes dry very slowly.
Warm air transfers heat to the wood causing the moisture in it to evaporate into the air. Again, the RH of the air must be low enough to absorb the water vapour given off by the wood. Drying kilns add warm air to the drying chamber, which transfers heat energy to both the wood and the water within it. The difference in temperature between the introduced dry air and the wet wood is often, but not always, quite small at the beginning of the kilning process. Water in the wood converts to vapour and evaporates through the wood surface into the air introduced into the drying chamber. The air temperature within a kiln is high, e.g., at stages in the wood drying process temperatures of 65.5° C (150° F) or more are used. At this temperature if the air stays at 70 percent RH it will eventually dry wood to approximately 10.5 percent MC (see figure 8.2).
If the air becomes too humid to dry the wood effectively, one of two things must happen for the wood to continue drying. First, further raising the temperature of the air in the kiln reduces its RH. Hotter air is capable of holding additional moisture released from the wood. Second, moving the humid air out of the drying chamber and replacing it with drier air will continue the drying process. Raising the temperature of the air already in the chamber is the cheapest option, but too high a temperature may lead to faults in the wood, particularly in some species more than others, e.g., surface checking as described earlier.
As timber dries, a moisture gradient develops inside the wood much like the earlier-described folded-up towel hanging over a washing line. In a wood-drying kiln where air temperatures are artificially high, generally the greater the temperature of the air acting on the wood, the steeper the moisture gradient within it, and moisture moves out of the wood faster. This also leads to faster evaporation of moisture from the surface of wood. Conversely, when wood is air dried and therefore experiences normal weather conditions, or if the wood is in service in a typical environment found in habitable buildings, RH is the primary controller of the steepness of the wood’s moisture gradient – air temperature in these circumstances has only a small effect.
For green wet wood to dry, as freshly milled boards or planks, for example, air must be moving to carry moisture away from the wood’s surface; this creates a place for the water deeper in the wood to migrate to, where it will also be carried away by the flow of air. If only a small volume of stagnant dry air surrounds wet wood, that air quickly becomes fully saturated with evaporated water. At that point no further drying can occur until that pocket of air moves away and is replaced by drier air.
Moving air carries moisture away from the wood’s exterior, thus drying the wood. But the air molecules adjacent to the wood surface stick to it. Air molecules just above the surface collide with the stuck air molecules and their movement is disrupted and slowed down. In turn, these air molecules impede the flow of air molecules just above them. As distance from the wood surface increases, the collisions diminish until air movement is unimpeded and becomes free flowing. In effect there is a thin layer of viscous “fluid” near the surface where velocity changes from zero at the surface to free flowing some distance away from it. “Engineers call this layer the boundary layer because it occurs on the boundary of the fluid.”19 (Benson, 2009, p 1) Within the boundary layer next to the wood the air is wetter (because it’s picked up moisture from the wood) and travels slower than the air above the boundary layer – it tends to hold the moisture taken from the wood close to the wood’s surface. A faster-moving air stream reduces the effect of the boundary layer and it sweeps away the damp air with its high-vapour pressure. The damp air is replaced with new drier air, i.e. air with a lower vapour pressure better able to absorb further moisture from the wood.
Whether wood is air dried or kiln dried the air entering the wood stack from one end has a lower RH than the air leaving the stack at the far end. Moving air leaving a stack of drying wood is cooler than the air entering it. The air cools as it transfers heat to the wood, thus enabling the drying process. If the air continuously passes through a stack of wood in one direction, the wood at the “upwind” end of the stack always dries faster than the wood at the “downwind” end. This results in unevenly dried planks of wood where the downwind end of a stack might be 3 percent or 4 percent wetter than the upwind side. In more extreme cases, the difference in moisture content between the upwind and downwind side of a stack may be 8 percent to 10 percent MC if the wood is very wet at the start of the drying process – in this case one possible result is the stack of wood may lean toward the drier side. This effect is more evident in wide stacks of wood, e.g., greater than about 2 metres (~6′), than in narrow stacks. Natural changes in wind direction and speed cancel out this effect in stacks of air-dried wood. It is only if a kiln operator is drying a wide stack of wood, or some particularly difficult to dry woods, that there is a real need to regularly alternate the air flow direction within the chamber. To achieve this, the fan blade rotation is reversed at evenly spaced intervals, e.g., every two hours, four hours, 12 hours etc. This upwind and downwind disparity in the drying ability of moving air in a stack of wood limits the size of a stickered pile of planks. This is especially the case with air drying where the yard owner really has less control over temperature, wind speed or wind direction. However, it should be noted that air velocity in either a kiln or in an air-drying wood pile is most important at the initial drying stage of wet wood because of its role in carrying away moisture from the wood surface. As the wood dries the significance of air movement gradually diminishes until the wood reaches about 20 percent MC. At this MC the primary critical factors for further drying are humidity and temperature, with the importance of air movement reducing significantly the drier the wood becomes.
