• 20 Oct

    A Sobering Little Aside on Safety

    One runs the risk of sounding like Chicken Little when discussing woodworking and safety.

    But one runs the risk of a lot more damage if one refuses to discuss it. And, much worse, even more, when not practicing simple, common-sense practices. Here a glimpse of what we teach our students here at Ebanista.

    First of all, no one comes into the shop without earphones, earplugs just don’t cut it, and safety glasses. Eye protection should be obvious but hearing loss is a one-way street. Once the fragile cilia in your ears are damaged, there is no repairing them. Hopefully, no one needs much convincing about all that.

    There are so many things one can do to ensure a long and prosperous and ten-fingered life in the woodworking shop. But there are quite a few you should never, never do. An example? Failing to leave a push stick on top of your table saw and then deciding to walk around and pull the board through from the backside. Before you know it, you have seven fingers. Of all of the woodworkers I have met over more than four decades in woodworking who have seriously hurt themselves, not only were doing something they shouldn’t have been doing, but they told me later that they knew as they were doing it that they shouldn’t be doing it. We tend to be overly confident when we become well-versed or good at something, putting safety in the back burner. 

    I make sure I take all the safety precautions needed each and every time I approach the table saw: I never turn on the table saw, or joiner or any machine without making sure that the floor in front of it is swept clean. If you are leaning over to make a detailed cut, you want your connection with the ground to be sure. Next, I always blow or brush off the table saw surface. If you can rig an air hose to hang from above, this is great. Sawdust can act almost like a lubricant, and make you lose a bit of control of your piece.  Next, check that fences are locked.

    We also never turn on the saw without making sure there are two items on the non-cutting side of the fence. One is a push stick. Do not, for any reason attempt to push a thin piece of wood with your fingers between the blade and the fence. From a Darwinian point of view, this is not a winning formula for ensuring a long line of people with your family name. And I always make sure that there is a fairly new pencil within reach. Why new-ish? Because it will be longer, and the eraser will be newer and stickier and this makes a wonderfully safe extend-o finger to pull little pieces of falloff from the blade without having to turn the saw on and off every few seconds or flick them away as if they were hot embers at a campfire.

    And the last thing we teach our students at Ebanista is to watch the fence, NOT the blade. The saw blade is not going anywhere. While watching it might be entertaining, it will provide you with neither safety or accuracy — two very important matters that almost always go hand-in-hand. If you are vigilant and make sure no shadow develops between your workpiece and the fence, you will be a very happy camper.

    Does all this seem like an interminably long list of items to check off before getting to work on a table saw? Or a jointer, or shaper?  I give you my word that after a very short time it will become so quick and automatic that you will not even notice it. And it will make you much more confident around your machines. And, although this seems unnecessary to have to bring up, the question begs asking whether you would rather spend a few extra seconds ensuring a long happy career in wood, or a painfully long time trying to figure out what went wrong, and why you might no longer be able to do this work you love so much?

    I told you that this was going to, by necessity, have to be a serious discussion. On the other hand, two guys walk into a bar……………….

    By Jonathan Cohen Woodworking
  • 06 Oct

    End Grain

    End grain. A simple concept, but slightly more difficult to master what it represents in the world of woodworking. We have talked about this on one or two of the other blog posts.

    To describe it in the simplest terms, a piece of wood can be thought of structurally as a collection of straws. The two broadest surfaces and the two sides, assuming that we are talking about a rectangular solid or a board, are the sides of the straws and are referred to as flat grain, while the two ends of the board, the open ends of the straws, are referred to as end grain.

    End grain and flat grain have very different properties and must be seen and dealt with in very different ways. From a woodworker’s and designer’s point of view, the most important fact is that wood moves- expands and contracts- so little along its length, (the same directions as the straws run) that movement there is safely ignored. However, wood DOES move across the board, or across the ends of the straws. The fact that boards move differently on different faces of a board seems to cause great consternation among woodworkers, but there are very time-proven methods for allowing the wood to continue to move in harmony for centuries to come.

    One of the main characteristics of the end grain in a piece of wood, is that being similar to a straw, it soaks things up much more easily than flat grain. More water. More oil. More finish. But, perhaps most consequentially, glue. The result of that is end grain is not generally your friend when it comes to gluing pieces of wood together. When you are gluing two boards up edge to edge, as in say a tabletop, the grain is flat (or side) and the wood stays on or near the surface. When the glue cures the two pieces are chemically bonded and are actually stronger at that joint, assuming well prepared gluing surfaces. The problem with gluing where one or both surfaces are those straws, the end grain, soaks up much more of the glue and therefore the chemical bond is relatively much weaker.

    The solution? Joinery. The entire purpose of joinery is to join two pieces of wood together in a way that provides the maximum amount of strength. There are two ways to do that. The second, is to create some kind of mechanical bond such as dovetails or a myriad of the extraordinarily complicated but beautiful joints employed in Japanese joinery where there are pins and wedges used to lock pieces together. But the first method is the most easily attainable and that is to form a chemical bond using one of many types of mastics, or glue.  The way to overcome the shortcoming here, that the end grain will suck the glue out of the joint, is to create a way of increasing flat grain to flat grain mating surfaces. That can be done in countless ways such as dovetails, half laps, splined miters, finger joints, and for me, a furnituremaker, not so much a cabinetmaker, the most important of all, the mortise-and-tenon.

    Very commonly used for example, where a horizontal stretcher connects to a chair or table leg. To a casual observer, it looks as though the stretcher, ( or apron), is simply butting into the leg. But we already know that the end grain of the stretcher will not afford much strength: we cut a rectangular hollow, called a mortise (think mouth) into the leg. Then, when the tenon (think tongue) is cut on the end of the stretcher and is coated with glue and slid into the mortise you have a pair of cheeks- the flat grain surfaces- mating and providing a strong glue/chemical bond. And voila! A strong joint.

    Another way in which end grain is very different than the other four (flat grain) surfaces of a piece of wood is its hardness. Press down on the sides of that bundle of straws and you can collapse them very easily. Press down on the ends of those straws and they have remarkable resistance. That is why vertical support members in a building are constructed with the grain running vertically. 

    One of the effects of this is it is much harder to plane or sand end grain than it is flat grain. Planes have been specially modified to deal with this problem by lowering the angle of the plane iron. ( Named, not surprisingly, a low angle plane.) An absolutely essential piece in any woodworker’s tool kit. And here’s a nice trick to remember: unless the end grain is precisely perpendicular to the length of the board, there is usually one direction to plane end grain that is a bit easier. This is most simply found by experimenting in different directions. Some woodworkers who are not as familiar with their hand planes as they could be might resort to sanding, but as most of you know by now, I consider that a vastly inferior and more inaccurate way to work wood. A tool that is very underrated and highly effective on end grain is a simple ( sharp- not the old rusty one in your Dad’s toolbox) flat file. Try it, you’ll be amazed how easy it is to get a polished finish on the end grain.

    End grain is, indeed, a different animal than flat grain in a piece of wood. It comes with some difficulties, such as needing to be extra careful when working it so that there is no blowout. But it can also be quite beautiful and placed where it can be a wonderful design feature. Look at some furniture pieces with through tenons. You can also go to YouTube and search for end grain cutting boards.

    Become good friends with end grain. It is worth it, and every piece of wood has it. You’ll see

    By Jonathan Cohen Woodworking
  • 08 Sep

    Wood Movement

    No, I am not speaking of a revolution here. Just the immutable fact that wood moves, and learning to be a woodworker means understanding this.

    Right now on youTube there is a young, blonde, Canadian woodworker (who interestingly calls himself Samurai Woodworker…). He’s jumping up and down and working himself into a lather about the idea that wood movement is myth, and we should all just pretend it’s not an issue. He then goes on to list a whole host of situations (outdoor furniture, furniture in badly heated homes, wood not well dried,etc.) where he graciously concedes that, OK, maybe it does move sometimes. I assume all the ranting is just to get more viewers, but I believe that kind of disinformation does not advance our cause.

    You can believe whomever you choose, but let’s just say that in more than 43 years of making handmade furniture, I have seen numerous examples of how foolish it is to not understand and design for your wood to expand and contract. I had my first tool box, built when I was about 20 years old, of maple and ebony and bronze, explode with a huge boom while I was sleeping. It was well-crafted, or so I thought, with frame-and-panel construction and it still sounded like a tree had fallen on the house.

    The problem in talking about wood movement is that it scares the Bejeezus out of so many woodworkers when they are starting out, as it seems so evil and mysterious. It is neither, but just as in every other aspect of life, a little knowledge goes a long way.

    Envision a piece of wood as a collection of straws. Imagine that a wooden board is a six-sided rectangular solid, with three “pairs” of surface.

    The end grain is represented by the open ends of the straws, and has many similar qualities. Moisture and nutrients pass along these “tubes” to sustain the tree. It also allows moisture to escape the end grain at a much faster rate than it does across its grain. 

    Therein lies the imbalance that dictates a woodworker need study their material.

    The amount of movement along the board- the length of the board in most cases is so minimal, that we rarely need to take it into consideration. Movement across the board is what does require planning. While our wood moves across the board in both width and thickness. The vast majority of wooden furniture is not much more than 8/4” or 2” thick. There is some movement there, but negligible. It is across the board, where the rubber hits the road. And when you start gluing up 30” or 40” wide tabletops? I’m sorry my young friend from north of the border, but this is where you are wrong.

    If you need more proof of our amazing material and its willfulness, I have read that in the time when the hoity-toity were prancing around in stone castles and a little remodeling was in order, the masons just stacked lumber between two walls and threw water on it. Don’t believe me? Note that little saplings can grow through stones, split rocks, and even perforate pavement. Nature will find a way, and this makes wood so wonderfully complex and interesting to work with.

    Okay, now that you are duly educated, relax and know that there is no shortage of manners in which to comfortably and effectively deal with this when designing/building a piece. The simplest is to make any large surfaces of plywood, which has its ornery-ness taken out by gluing multiple substrate veneers at right angles to each other. Easy, but many fine woodworkers want no part of man-made materials in their work. Another way then is to control and work with the wood movement rather than fight it.

    For cabinetry, the problem is most commonly in door panels, and Frame-and-panel construction was developed centuries ago to deal with wood movement. A fixed dimension frame with a wide panel snugly filling it, but not glued and with space for the panel to expand into. For furniture, which is most of my work, the issue is usually with wide table and desk tops. The method I most often employ is to attach (notice I very specifically did not say glue — do NOT glue it!)  a batten to the underside of your wide solid top. This is held in place by a mechanical piece –think wood screw — that draws the top down flat to the batten. However, and this is everything, the screw cannot pass through a round hole. When the top expands the screw would be locked in place by the small hole and would be in direct conflict with the movement of the wood. The hole bored for the shaft of the screw must be elongated into kind of a through mortise or slot. Then the tension of the screw head pulling against the threads hold the top flat, while the elongated holes allow the top to move across its width all the while resting comfortably.

    There are literally hundreds of other methods for allowing your wood to move through the seasons and across the centuries. Rather than think of this necessity as a burden, I enjoy making it a design consideration. If you have a chance to look at a few pictures of my work at ebanistaschool.com or www.jonathancohenfinewoodworking.com you will notice several examples of how this can be done. Don’t let the wood movement intimidate you, but use it as a creative advantage.

    By Jonathan Cohen Woodworking