Thursday, May 31, 2007
Here are the lathe tools that I use. They are all shear cutting tools and never used as scrapers. I haven't come across any spindle turning (versus bowl turning) shape that I can't manage with these few tools. Actually, I could do without a couple of them. The large roughing gouge and the sizing tool on the right are nice additions but not necessary. I'd say that a quality parting tool, 3/4" roughing gouge, 1/2" detail gouge and a 1/2" or 3/4" skew are all that one "needs". I like high speed steel for the ease of grinding (hss doesn't lose its hardness unless heated very hot, so a little bluing doesn't affect it) and the durability of the edge. Lathe tools do a great deal of cutting in a matter of seconds and constant grinding and sharpening are essential. A sharp lathe tool is the only kind that works. I often let students try to work with a worn tool, and work is best way to say it! Then we sharpen up and the fun begins. I cannot turn with dull tools and imagine that much of my turning ability is knowing when to sharpen. If I was to buy just one lathe tool, it would be the 3/4" gouge. This one tool can take you from roughing to finished work and create some lovely shapes. Learning to expand the uses of just a few tools is a great way to gain skill and confidence while saving a buck as well as valuable shop space!
Wednesday, May 30, 2007
Each morning, I sit on my porch, watch the sun come up over the trees and look at the birds. Today, my porch time was coupled with learning to use the panarama stitch mode on my shiny new camera. This is my favorite part of the day, and if I'm not careful, can stretch way too far into the time when I should be working.
Monday, May 28, 2007
Here is a spoon that I carved yesterday for a friends birthday. With it you can see the carving knife that I made a couple of years ago (looks like I made it in prison, right?!) and a hook that I forged to hang it. I haven't made any object that has more to teach about the nature of grain direction in a chunk of wood. I know that for some, this may come dangerously close to seeming too "crafty", but I assure you, it ain't as easy as it looks. I try to work with the shape of the piece and its fibers to decide all of the design aspects as I carve. This has led to some pretty ugly spoons, but I like the challenge. Both Roy Underhill and Drew Langsner have some good info on spoon carving. Personally, I like to make simple spoons that show the tool facets all over and only scrape and sand the interior of the bowl. I carve them green, usually from crabapple tree (this one is cherry) and then once they are almost to final size, I put them in a paper bag to dry. A little finish surfacing and some walnut oil finish them off. I get much joy from seeing a well used spoon of mine when visiting friends, the only problem is that I always give the good ones away and keep their ugly cousins for myself!
Sunday, May 27, 2007
Here are a few of the blades that I made in the forge this week (the marking knife was made by Josh, nice job). By the end of the week, I had made a shovel and a few of the implements that turned out to be essential to managing the fire. Once I could control the fire better, the whole process started to come into focus. As I had hoped, after my less than stellar first attempts, persistance and experimentation paid off. The gouge pictured is especially exciting to me. I started with an old coil spring and successfully straightened, shaped, annealled, hardened, tempered and sharpened it. There it is, a whole new world.
Back to purchasing tools. One thing that I've been meaning to mention is to avoid buying sets of tools such as carving or turning gouges. Normally you'll find that the "savings" is eaten up by having a tool or two in the set that is of little use to you. I prefer to slowly purchase one high quality piece at a time when the definite need arises. And don't be afraid to buy yard sale gouges (as long as they are cheap). Learning to sharpen a cheap gouge is a lot less harrowing than some $40 swiss made. Most of my gouges were bought this way, the only problem being getting unusual sweeps and sizes. As hand tool users, we are in a unique position. What many yard sellers think of as Grandpa's bucket of rusty junk, can be pure gold to us. One of my great joys has always been the time I spend bringing one of these old tools back to a useful life. These days, I'm finding satisfaction in making it in the first place!
Thursday, May 24, 2007
After sitting around my shop unassembled for two months, I finally took the time to get my chainsaw mill up and running. The idea of buying one had been on my mind for a couple of years, but one of the things that I love about green woodworking is not having to mill lumber. Cherry changed that. I am fortunate enough to live in an area with abundant cherry and have enough falling on my own property to keep me busy. The problem came when I went to split the billets. Thinking it would be as well behaved as maple was my first mistake. A long story short, I was sickened to see the splits run out uncontrollably. To see a pile of "almost" parts that would only serve to heat the shop, and having orders to fill, finally drove me to buy the mill. I figured that the material saved would soon pay for the mill and the joy of seeing the tree better utilized would make up for having another gas burning noisemaker. So with my helper Josh King, I ventured to into the woods and got to it. Because I am working with a small tree that fell on its own last year, I decided to rip it down the center and do all of the final cutting on the bandsaw. We set up the runners, set the depth of cut, hooked up the auxiliary oiler and proceeded to flood the engine, of course.
But once we got it started, it literally glided through the cut (about 6 feet long) in about 3 minutes. Below you can see the result. I don't know that I would use this tool to mill anything thinner than 4 inch planks, the wasteful kerf and time eating sawdust would be too much, but for chairs it works great. By milling thick planks and crosscutting into a lathe ready length, I can easily get the wood to the shop, and cut it down with minimal waste on the bandsaw (with which I can follow the fibers just like a split). Do I wish I could avoid this extra work, yes. But the cherry has captured my imagination and working a tree from my own land is truly gratifying.
I owe a special thanks to Rich Pallaria for his help finishing the grading and drainage around the shop and to Josh King for not laughing when I flooded the chainsaw.
Tuesday, May 22, 2007
I will be returning to tool buying recommendations soon, but for now, my attention has turned to tool making. My friend Rich came over yesterday and we fired up the forge and started to work some steel. I have been making tools for years out of necessity and have decided that it is time to start learning the ins and outs of real blacksmith technique. By the end of the day, Rich and I had tried all sorts of new techniques and fallen into the pitfalls of every one! I have always been interested in learning new things and after years of tormenting myself during the learning process, have come to relax and enjoy the perils of the unknown. Lately I've been working on many different fronts such as writing, building stone walls, tending fruit trees, book illustration, small engine repair, syrup making and as always chair design. Any one of these pursuits could drag me into a cyclical spiral of expectation and failure, before any real hope of skill and success. Perhaps the only expectation that is always appropriate is that anything worth learning is made up of unexpected difficulties, and the courage to weather the process of learning, is the real achievement. So at the end of the day, with a bunch of misshapen and burnt up steel, I felt good. After all, I'd spent the day outside, with a good friend, learning that there is a whole new world to explore.
Sunday, May 20, 2007
Nope, this is not a posting about carving a seat! One of the great joys of chairmaking for me is how much of the actual work is guided by sense of sight and touch. This keeps me very attentive and involves me physically in the act of making, knowing that at any moment, the work could go awry. The feedback from our hands can be one of the greatest sources of information if we know how to use it. The image above shows how most of us would "read" the surface quality of a piece. The fingertips, with all of their nerve endings do a fine job. The problem comes when we are not as interested in the surface quality as the shape. The fingers can move independent of each other and our ability to recognize their relationship to each other is limited. Below is a photo of "reading" the shape with the whole hand while running along the curved edge. When touching the piece this way, the information is easily processed and any inconsistencies become apparent. Here is the funny thing, often I demonstrate this to students and still they use only their fingers! I guess that we spend so much time trusting our fingertips that involving the whole hand is unnatural. Give it a try, go up to any curve anywhere and touch it using your fingertips and then use your whole hand, I think you'll "see" the difference.
Saturday, May 19, 2007
As with many cabinetmakers, I followed my interest in handtools to handplanes and planemaking. Handplanes have come to represent "fine craftsmanship", hence their presence in magazines, catalogues and logos. Any visit to a handtool forum and you will find that much of the conversation revolves around planes. It is a great introduction to cutting wood with a fixed blade and sharpening etc...but there are other tools that offer greater freedom awaiting. I still flatten and joint my seat blanks with a handplane, which teaches me a great deal about the hunk of wood that I will be carving, there is great satisfaction to be had in practicing this skill, but I try to remember that the handplane is a means to an end and not an end in itself.
If you have a 20" jointer and planer, you can ignore this! The scrub plane is the first plane used to flatten the surface of a board. It is fitting that this post follows the one about inshaves having too curved a blade, because it is the curve of the blade that distinguishes the scrub plane and makes it work. The curved blade reduces the width of the cut taken and ensures that the edge of the shavings are tapered which reduces tearout while enabling a heavy cut. If you tried to plane "with" the grain and find yourself going the wrong way, the tearout could be dramatic. By using the blade crossgrain, the fibers being sheared are always supported by the fiber next to them, this gives a reasonably clean cut, which is fine for this early stage of flattening.
The scrub plane is not truly "essential" to flattening a board. The same results can be achieved with a regular plane, just more slowly and with more effort. But the speed gained and ease of creating a scrub plane makes it a good plane to start your collection. The photo shows three different scrub planes. The plane in the foreground is a Lie-Nielson scrub plane, its quality construction is reflected in its price. In the middle is a plane that I made myself and in the back is an old wooden jack plane with a reground blade. Below you can see the shape that I find best for my scrub blades. If you are considering acquiring a scrub plane, I'd encourage you to seek out an old wooden smoother or metal plane and simply reground the blade. That's it. It is simple and cheap and will give the satisfaction of using a tool that you have "made" yourself. All that is required is the rounded blade, a wide throat opening and to set the chipbreaker back from the edge. There is lots of good info on planing technique available at the woodworking forums posted on the right. Good luck
Thursday, May 17, 2007
Above you see a few inshaves. Really, the only one that I use is the one on the left. It is available from Highland Hardware under the name "oxhead". I have seen all types of inshaves and found this to be not only my favorite for its shape and ease of sharpening, but also the value. While it is not a "beautiful" tool I have found it to be easily tuned and just the right shape for the job. The inshaves on the right are antiques (you can see the imprint "cast steel") and I think that their shape is very telling. You may have noticed that the inshaves generally available have a tight circular radius, yet the shape of these old tools is relatively flat. What gives? Somehow, I think that the toolmakers today have looked at the windsor seat and decided that to carve it takes a tight radius. I haven't found this to be the case. The shame is that these inshaves are often beautifully made (with a cost to match), although I find the geometry tough to sharpen. Here is the difference, imagine trying to flatten a board with a small blockplane. It would take a great deal of care because it could only take a small cut and a limited amount of information about the surface. The idea is generally to take a larger plane that will take in more information and "map" its shape onto the wood. The same goes for carving seats. An inshave with a tight radius may be more suitable to bowl carving. If you already own an inshave with a tight radius, you don't "need" to buy any other, but if you are in the market for one, I've found the "oxhead" to be a great buy. I'll go into the use and sharpening of this often misunderstood tool in another post.
Wednesday, May 16, 2007
I couldn't resist taking this photo. Lately, I have been making chairs in cherry, which has me at the lathe more than the shavehorse. When I started on a couple of combback rockers, I guess I got a bit excited at just shaving the day away!
Below is a Stanley 151 spokeshave with a replacement blade by Ron Hock. A spokeshave is the equivalent of a small hand plane, only it works in the world of the curved as well as the flat. This is a great spokeshave and the only flat soled shave that you ever really "need". I like it because it is inexpensive (ebay), adjustable, has readily available replacement blades and feels great using. The blade replacement is the key to transforming the tools from suitable to excellent. By adding a thicker blade, you tighten the throat opening (often too wide with the original thin blades) and dampen vibration, not to mention the keener and longer lasting edge. The only problem is that the blade will cost more than twice the cost of the tool! I figure on about $45 dollars by the time I've got it together. Now for that cash you may be happy with some other tools such as a Lee Valley shave. They seem to me to be a fine choice, although I find them a bit top heavy. There are some other higher end shaves designed by Brian Boggs and produced by Lie-Nielson. Wow, are they ever gorgeous (see, there's a tool junkie in me after all). But they don't have adjusters which can confound early attempts to get good results. I wouldn't recommend one until after you can comfortably handle an adjustable shave. Honestly, there is no task that I haven't been able to achieve with my trusty 151. I do use some old wooden spokeshaves, but I only use them for carving tasks (where their low angle blade shears well) and find no advantage to them when shaving spindles etc... There is a cottage industry in the production and promotion of these shaves and they are well made tools. I just don't find them necessary or advantageous for the cost. And remember, my goal in these recommendations is to enable folks to aquire some basic tools that are going to form a solid chairmaking collection.
Monday, May 14, 2007
I was speaking with a fellow who is going to be taking a class with me in December. He hasn't made chairs yet and owns no tools. He is excited to get started and asked me what tools he should be acquiring. When students come to my shop, I invite them to bring tools that we can discuss, tune up and use, but they are not required to bring any at all. As may have become all too apparent from previous entries, I avoid tool buying at all costs (forgive the pun). But in talking to my future student, I realized that staying out of the fray is no longer viable. So I am going to make some basic recommendations for some tools that I think are worth buying and essential to chairmaking. One important note, I am in no way connected to any toolmaker or company and my recommendations are based on my personal experience and represent only my opinion (for what it's worth). Luckily, my students have brought with them just about every chairmaking tool made so I have had a chance to try many of the tools out there, for better or worse.
But before I start naming names, I want to share my own beginnings in tool acquisition. The photo above is of a piece of steel that I bent and sharpened to approximate an inshave. I made my first chairs with it and had fine success. I show it to make a a point. It is more important to understand the task at hand, the behavior of the material and how the tool works than to have the tool itself. Most of the time, with a minimum of ingenuity, you can get the job done. Don't get me wrong, much of the time my crude first tools are simply a means to understand which tool I should buy. The storebought "proper" tool is no guarantee of results, especially when it falls short of the requirements of the task. Sadly, I've found that many of the tools marketed as "chairmaking tools" seem better suited to coopering or some other woodworking task. I have heard the lament of many students with a chest full of tools that have learned that they are less than optimal for chairmaking. Not that they can't be made to work, but for the prices these companies charge, they should function better. I prefer to expose students to the skills that they will need first and let the necessity for tools follow, once the understanding is firmly in place. It is a tough lesson, a tool can extend your skill, not create it.
Forgive me if I seem cynical, it is difficult to combat an industry with thousands of people who spend all day coming up with new ways to convince us that the next pricey tool will set us free. I will be looking hard at my (beloved) collection and try to come up with some recommendations that will justify the money spent.
Saturday, May 12, 2007
Of all of the images that I've posted, this one gave me pause. I recognized that there is a small wedge of the world interested in green wood chairmaking and that I am reducing it to an even smaller percentage willing to do it with an electric drill! It also brought to mind an encounter that I had last year while at the Colonial Williamsburg Woodworking in the 18th Century conference. While there, I met Roy Underhill of PBS's The Woodwright's Shop. Roy is the costumed champion of old technologies, I grew up watching his show. He shows the simple ways to achieve great results while expanding self reliance. This is right up my alley. He also authored some great books that are an inspiration to me still. I had a fine time in Williamsburg and met a lot of great folks who share common interests (I'd return in a heartbeat if they asked!). As I was taking a final stroll through the town, reflecting on my week and looking forward to returning home, I stopped at a cross walk and waited for the light to change. I looked up just in time, there was Roy, whizzing by in a minivan while chatting on a cell phone.
And so it goes...
There are a few keys to getting the results that I've shown with the bits that I grind. There is only one speed for the bit to spin, as fast as possible. It is the rate that the bit is advanced into the cut that the control is exerted. The idea is to hold the drill back, not push it, and let the bit do the work. The size and clearance of the chips can help decide the rate of feed. These bits are aggressive and too much pressure can be disastrous.
The other technological breakthrough that I like to employ is the clutch. Cordless drills (and a corded Ryobi drill) have a clutch that can be set to various settings to stop spinning when a certain resistance is met. Manufacturers alway label the heaviest setting for drilling. I do just the opposite and use the lightest setting. Not only will the bit stop cutting if I am not drilling straight, but it will stop when the bit emerges from the cut and tries to take that one last chunk that will cause a blowout. When the bit stops, let go of the trigger and pull back a little bit (often running in reverse will help). Pull the trigger all the way and advance SLOWLY through the last bit. This can take some real practice, I know "anyone" can use a drill, but there is more to getting excellent results than just pulling the trigger. A drill is like any other hand tool, practice pays off. The results and freedom gained can be amazing, I think even Roy might be impressed, maybe I'll call him.
Friday, May 11, 2007
Here is an image of grinding the web on a drill bit that is left after grinding the wings. The tricky part about this is that the wing that is pointing down is dangerously close to the grinding wheel and the slightest encounter will send you back to step 1. Not a big deal, but it's better avoided. I avoid hitting it by keeping the wing that is pointing up a little past vertical (towards the grinding wheel). By keeping the wing that I can easily see close to the grinding wheel, I can generally keep the other one in the clear. The other key to grinding the web is that as I proceed to push the bit into the wheel, I let it come off of the block a bit. This happens quite naturally because as I push into the wheel, the amount of metal that is cut gets greater and the bit wants to slide to the side. You can see the result of this in the photo below (how about that new camera!).
There is a small learning curve to grinding drill bits, luckily we all have a myriad of dull beat up twist bits to practice on. Once I started grinding bits, I was amazed at how much steel the actually have! I learned using bits that weren't high speed steel, just my old junkers. Even though they lose their temper, they actually work fine, just not for as long. By the way, I've read that quenching high speed steel is not recommended, when it gets hot slow down and let it air cool.
Here is the resulting hole that the bit made. Notice the shavings. And below is the exit hole. I didn't use any backing, just drilled right through. For me, this grind solved one of the most vexing drilling problems in chairmaking, all of those holes that need to start at an angle and come through a curved piece (near impossible to back). I know that many excellent makers prefer auger bits and simply stop when the screw comes through and come back from the other side. It obviously works fine for them. This is a personal preference. I will post some tips for drilling clean holes soon.
Wednesday, May 9, 2007
Lots of pictures today (a great way to show off my new camera!) The photo above shows the way that I use my wheel dresser to make a shape on the side of my grinder that will correspond to the wing of the brad point. I alway make sure that the corner is lower than the flat of the wheel that I use for general grinding. The sharper the corner, the deeper the wings. I did some measuring of the angles that I use today because honestly I've never bothered. Experimentation is the key and the numbers that I use can vary depending on the performance and intended use of the bit. I measured the angle of a bit that I use all the time and found it to be about 35 degrees (see below). The steeper the angle, the more aggressive the bit, until at some point, the edge is too thin to be effective. I always use high speed steel because it doesn't lose its temper until it is red hot, a little bluing is fine.
Below is the jig setup that I use while grinding. My measurement for this bit is about 2 degrees off of the axis of the wheel. By adjusting the angle that I clamp the block to the rest, I can adjust the length of the center point. A greater angle makes a shorter point. As you can see, it is the side of the wheel that actually forms the center point.
Below is the first cut that I take. I make sure that the existing cutting edge is horizontal and proceed to grind. After a moment, I judge whether the bit is far enough over to form the proper point.
I switch back and forth between the two sides in an effort to let the bit cool and to keep the wings even.
Below is the bit with the wings ground. All that remains is to remove the web (you can see it in the center of the bit) that has been left by the grinding. I'll post the web grinding and tips for using soon.
Tuesday, May 8, 2007
Here is a close up photo of the grind that I use on my drill bits. I'll be showing how to grind it soon. The picture below it is of the bit while spinning. It brings up an important issue. Every bit and every chuck have some degree of runout, they don't spin perfectly. When chucking up a bit, try spinning it at high speed and look at the point. If it moves erratically, try loosening the chuck and shifting the bit a quarter turn. When you have the bit in the optimum position, the runout in the bit and the runout in the chuck will cancel each other out almost completely. I made a mark on the chuck of my drill and every time that I use a new bit, I make a corresponding mark on the bit once it spins true, then when I go to use the bit, it is as simple as lining up the marks.
Monday, May 7, 2007
The round mortise and tenon is one of the simplest woodworking joints to make. There is probably no more widely used woodworking skill than drilling a hole. But to get accurate and repeatable results just using a drill and drillbit takes a bit of care. The picture above shows the tools that I use to fit my mortise and tenons. I am going to start by focusing on the drill bits. I don't do any of my drilling with a bit and brace, I know, I'm no purist. When I started making chairs, I didn't own a brace and a good set of bits was not in my budget. As a cabinetmaker, I became very familiar with a cordless drill, and that's where I've stayed. I grind my own drill bits using high speed twist bits that I fashion into long spur brad points. They allow me to enter a cut at almost any angle (vital in chairmaking) and leave a beautifully clean hole and exit cut. Why grind my own? I have bought just about every bit on the market and found them to be lacking and costly. However, the biggest problem that I have with them is that they are difficult to sharpen, meaning that from the first time that I use them, I have to accept some lessening of their cutting quality. A drill bit should be judged like any tool in the shop, it is a cutting tool that can be sharpened and modified to perform at its maximum. The method that I use to grind bits is simple and forgiving (I'll be covering it soon).
There are a couple of basic ideas about drilling (with a power drill) that I find useful. The same bit drilling into different woods will yield different sized holes. If you drill a block of hardwood to test your tenons for a pine seat, you'll find them swimming in their mortises. It is vital to test at least one of the tenons in the actual wood that it will be mating with to understand the way it should fit in a test block. Perhaps a supersnug fit in the test block will be just right in the pine.
Whenever I drill, I use very light pressure and high speed, my bits are very aggressive. Always start with the highest speed to get a clean entry hole and let the drill advance at a speed that clears the chips cleanly. Going too slow can burnish the hole. I am careful to hand fit each tenon to it's mortise, one at a time. It is one of those times that I slow down to take extra care. I think of it as a time to pay tribute to the time that I've already invested in the parts that I am joining. I love the look of a clean joint. It may sound ridiculous, but getting a few different species of wood and making some practice holes with your drill bits can be enlightening. Are the holes clean and accurate? Did you blow out the exit? Are they so dull that they smoke? Do the chips come out in beautiful curls or dust? Remember, the round morise and tenon is a terrible glue joint, and no glue can make up for a burnished, oversized hole.
Saturday, May 5, 2007
If you were able to take anything from the first and second postings on the topic of grain direction, I would hope that it would be this, wood is nothing more than a bundle of fibers and to shear it cleanly, each fiber needs complete support. Diagnosing which way will offer this support is as easy as cutting one direction and then judging the surface quality. This is a fine way to proceed and most likely the way that we truly learn to "read" the grain. However, to really arrive at the correct direction takes a willingness to not settle on "good enough" and reach for the sandpaper. I am convinced that the joy of hand tools is best experienced when they are working fast and final, plus my bottom line depends on it.
The photos above show a similar shaped cut out in two different orientations on a plank of wood. Once again, I've accentuated the growth rings to represent the direction of the fibers. As is indicated by the arrows, the cutting would proceed in opposite ways for each. This is a common occurance in chairs, where all sides of a workpiece are shaped. You can see that by cutting in the directions that I've indicated, each fiber will have the full support of the fiber next to it.
The difficult area is the overlap region where the cut is either perpendicular or parallel to the grain (in this case at the bottom of the cut out). In these areas, you can cut either direction but quickly run into the reverse grain. My strategy for such areas is to always leave a flat "landing strip" at the bottom of the curve to accomodate easy starting and stopping. I also do this in turnings, be it the largest diameter of a bead or the smallest of a cove. The flat area is essential to getting a clean cut and remains until my very last light cleanup pass, where I round it out (a light slicing cut can often confound the rules of grain direction). Good luck, be patient, and take light cuts!
Friday, May 4, 2007
Time for another swing at grain direction. The photo above is of a quartersawn piece of cherry. I used it because of the easy to see growth ring lines that can be used to represent fibers. As you see, I've accentuated the lines with a marker and cut the top of the board at an angle. The basic concept that I am trying to convey is that with support, fibers will shear cleanly and without it they will deflect and break below the surface causing a rough uncontrolled result.
Before I go into the photo, I'd like to introduce an idea that we all already practice. Imagine cutting a celery stalk (across the stalk). Do you automatically imagine a cutting board as well? The cutting board supplies the backing that will allow us to cleanly shear the celery. It is the same idea when we shear the fibers in a piece of wood, they need support.
Now back to the photo. To cleanly shear the fibers, which way would you cut? Forgive me if this seems too simple, it can very quickly become perplexing. By cutting the direction of the arrow on the right, each fiber will be fully supported by the adjacent fiber. If you were to cut the direction indicated by the arrow on the left, there is an area, albeit small, that has no support. This causes the fiber to deflect and break rather than cleanly shear.
I have been wracking my brain for years to come up with a simple truth to apply to all situations to explain which way to cut. Here's what I've come up with. In any cut that is not parallel or perpendicular to the fibers, the direction to cut will have adjacent supporting fibers that extend beyond the fiber being cut. Looking at the photo above, you'll see that it is a simple and clear case of this. The only problem would come at the top point where there would be no adjacent fibers beyond it risking a blowout. I'll address this soon.
Most of the shapes that we wish to make in wood (especially in chairs) aren't always so simple, but the need to have supporting adjacent fibers remains critical. I invite feedback on this topic because as much as I have a desire to help my fellow woodworkers, I could use your help in honing my ability to convey this difficult concept. I will cover some more complex shapes soon.
Wednesday, May 2, 2007
I've decided that it is time to try to tackle the topic of shaving wood and grain direction. For handtools to be effective, they must be sharp and applied properly. The name of the game is knowing where to push or pull the tool in relation to the grain to get the desired result. While it sounds simple, it is a difficult concept to put into action. I have explained this countless times and had my student nod knowingly and then proceed to cut the wrong way! Of course, I take the blame as the instructor. But in discussions with other instructors, I've come to see that imparting a working knowledge of how to cut the fibers properly is somewhat of a holy grail of teaching woodworking. It seems to me that no single concept is too difficult to convey, but it is the adding up of the concepts on the fly that takes work. As you take each cut on a piece of wood, the rules can change. Hopefully, with a careful approach and a few postings, I'll be able to simplify it a bit.
Let's start by talking about working with split green wood. When the wood has been split, as opposed to sawn, the fibers will run roughly parallel to the outer surfaces of the piece. Shaving the wood can be viewed as almost a peeling process. Think of a banana. When we peel a banana, we are exploiting a weak bond between the skin and the fruit. With green wood, it is very similar. A drawknife will slide inbetween the fibers and prefer to follow along them because it is more difficult to cut across them. This "peeling" leaves a clean surface that is perfectly parallel to the fibers. An interesting difference between a sawn piece and a piece shaved to follow the fibers is that the only exposure of end grain of a shaved piece is at the ends. Any time that you cut across a fiber, be it in the middle of a board or in a carving, you are exposing endgrain. This means that in sawn or carved pieces there will be endgrain exposed all along the piece. The weakness between layers becomes exposed in this "all over" endgrain and the wood can break below the surface as a result. It is this subsurface damage that is often the first clue that we are going about cutting incorrectly. Luckily, preventing the weak bond between the fibers from breaking is as simple as offering them proper support. I'll go further into that soon.
Here is an experiment that may help clarify what I have covered here. Take a piece of sawn stock, perhaps a piece of 1X pine from the hardware store. Put it on edge in the shavehorse or vise so that you can shave the 3/4" dimension. Take a sharp drawknife (you have plenty of them right?!) and run it down the surface. Now the simple adage of "go the other way" if you get tear out, doesn't apply to the experiment. Go the wrong way. It will split and tear out etc...that is alright. Keep trying to get under the tear outs and soon the drawknife will find the fiber line. Most likely, it will not be parallel to the original sawn edge. As soon as the wood shaves smoothly, stop. Any further and you are likely to start cutting across the fibers in the opposite direction. It is vital to start seeing any board as a bundle of fibers. Once you can see the fibers and the way that they run in the board, you can learn to work with them, and that is when things start getting fun.
In the photo below, you can see that the shaving is very crude and fractured from the heavy splitting action of cutting the "wrong" way. But take note of the clean surface that it has left behind running parallel to the fibers.