Wednesday, February 28, 2007

Waterstone Tips

I have used waterstones to hone my tools for years. There are a few major lessons to be had with them. Number one is that the reason that they cut so fast is also their greatest problem. As the particles on the surface break down to reveal fresh sharp particles, giving fast cutting, the stone quickly becomes misshapen. For most tools, at least one side of the tool requires a perfectly flat surface which can only be honed on a perfectly flat stone. This means that the using waterstones demands almost perpetual maintainance. Luckily, it is as easy as rubbing them on a drywall sanding screen on a piece of plate glass. The good new is that many of the common problems with sharpening can be traced back to using stones that aren't flat.
Rubbing the back or bevel of a blade on a dished out stone will slightly round the edge. When moving on to the next stone, which is harder and less likely to be dished, the edge no longer makes contact. You are literally no longer honing the edge! To test for this kind of rounding, hold the tool so that light is bouncing off of the edge and move it. If the light rolls over the edge, you've rounded it. Now you must either reflatten the back or grind away the offending edge. I know that sandpaper on glass offers another solution without the constant flattening, but then you are buying lots of sandpaper and messing with gluing it down. Also, fresh particles are not constantly available, the paper simply gets dull. But, my main reason for preferring stones is the slurry.
Slurry is the mixture of particles and water that the blade rides on as you hone. The greatest benefit of this is that the more water you use, the fresher the cutting surface, the faster the cut. The other benefit is that as you hone, the slurry starts to dry and the particles in it break down. This dried slurry acts as an inbetween grit, allowing the surface you are honing to be polished to a higher level than the grit labelled on the stone. When you move up to the next higher grit stone, which cuts slower, there is less work to be done. On the last stone, normally for me an 8000 grit, I let the slurry go completely dry and turn black (that's the metal coming off the edge) and polish until the edge not only has a mirror finish but looks almost wet. During this final honing, I only pull the blade towards me, the last thing I want to do is plow a razor sharp edge into a bunch of grit! I find that combination stones are a cost effective place to start with stones. Avoid grits below 1000 as they wear too quickly to be of use, sandpaper on glass serves much better for such rough work, although, once the back of a tool is flat, it should never be necessary to return. When honing a blade with a flat polished back, never hone the back on the coarser stones, only on the finer stones to remove the burr. Stay away from any stropping of chisel and plane blades, you cannot help but round the edge. Later I'll address how this slight rounding is exactly what gives drawknives and carving tools their versatility and control.

Tuesday, February 27, 2007

Gerry Felix, Guest Blogger pt.3

Whew, on two counts: completing the rocker in timely fashion and completing the drive home in some really nasty weather.
Pete once again proved up to the instructional challenge, this being my second visit. Can't say enough about the facility, having gone from the basement to a real chairmaker's workshop. The lighting was superb and the wood stove provided plenty of heat, in spite of a few bitterly cold days.

Work days were very full, but not overtaxing. We held to a basic 8-5 schedule, which proved to be about right in completing the chair in just over 6 days. Added benefit to me was observing Pete work on his new rodback armchair. I brought along some of my tools, but used Pete's the majority of the time. Razor sharp. Pete uses a variety of grinding and polishing wheels, then onto waterstones and strop. I thought mine were adequately sharpened, but I was wrong. We tuned up many of my tools as we worked our way into the week.

So now my challenge is to duplicate my efforts and complete a chair on my own, and I feel confident that I can do just that. Preconceived notions led me to believe that one merely added rockers to regular chairs. Not so. The undercarriage is altogether different and assembly takes a great deal of adjusting and treaking to arrive at total balance.

Today I'm still in a recovery mode, but tomorrow it'll be time to bend an arm and crest. I know I'll have questions along the way. I also know that I'll have Pete there on my wing, ready to bail me out.

PS: got my scrapers coming along nicely. Thanx.

Monday, February 26, 2007

Sharpening, a Beginning

As someone who works primarily with handtools, I've found that fully half of my understanding of the craft has come in the way of metal working. There is no possible way to cover the entire topic in one entry, so I'll start with basics and hope to build on it in later entries. The basic idea is to get a sharp piece of metal to cut a chosen piece from a chunk of wood. The wood basically sits there while I decide what shape of metal or metal housed in a jig (planes etc..) will take the desired cut. Now sharpening is as easy as sanding, you shape the metal with a rough grit (the grinder) and then follow through with finer grits until the two surfaces that make up the edge have a mirror finish. In the photo, you see a sharpened screwdriver and the mortise and paring cuts that I took with it. I did this to demonstrate that there are no magic tools. Yes, some work better than others, but with understanding, even a crusty old screwdriver can get the job done.
I started sharpening with an old hand cranked grinder and ran every chunk of metal I could find against it! I feel that a grinder of some sort is essential to fluent sharpening. Imagine the difference between removing 1/4" of wood with a drawknife or with 80 grit sandpaper. The grinder establishes the shape, the stones polish the surfaces and form the burr. The burr is simply the tiny unsupported bit of metal right at the edge of the tool that bends over as you abrade the surface. As the surface gets polished to a higher sheen, the tiny bit of metal connecting the burr to the edge gets smaller and smaller, until the burr falls off. Getting the burr to drop off cleanly is a huge part of establishing a fine edge. The edge is now sharp, there's just one question, is it the right shape to cut wood?
Many edges can shave hair, balance on your fingernail, cut flesh and whatever else method you choose to check for sharpness, but to cut wood, the geometry must be correct. The best way to learn to sharpen is to focus on getting two flat surfaces to meet, such as on a chisel. The bevel, concave from the grinder, will contact the stone in two places. At the edge and at the back of the bevel, this helps keep it from rocking on the stone. The type of cut that this edge can take, outside of a plane or spokeshave is limited to chopping and paring. The flatness of the surfaces directs the cut. Later I will talk about the slightly rounded surface used in carving tools and many freehand chair tools. There are many different tools out there that promise freedom and fun, I tend to try to find ways to achieve the results I need without buying a lot. Sometimes I cost myself in time while saving money! The one type of tool that I am always comfortable spending on is sharpening equipment. Some things to consider are: quality set of water stones, a piece of glass with sandpaper or drywall sanding screen (for keeping the stones flat), a slow speed grinder with aluminum oxide wheels, a quality tool rest (the one that comes with the grinder is generally poor), a piece of leather and honing compound for a strop, and my new favorite, the high speed buffer with a beartex wheel and a hard felt wheel. With a great sharpening setup, all else falls in place. And remember, the easier sharpening is in your shop, the more likely you are to actually do it.

A Better Joint

The round mortise and tenon is one of the easiest joints to make, it is also one of the worst when it comes to gluing. Glue only works to bond wood with strength when the long fibers meet long fibers (as opposed to the endgrain). The round mortise is almost all endgrain making it a poor glue joint. As seasonal movement causes the tenon to shrink and swell, the glue bond is stressed and in time will fail. The through tenons that we use in chairs are wedged, to flair the tenon and create a tighter fit. One day last winter, I looked at a wedged tenon in one of my chairs around the house and noted a gap along one side of the wedge. It reminded me of something I read in Bruce Hoadley's book Understanding Wood. He noted that by splitting the tenon, we supply a plane of failure, which relieves the stress on the glue around the tenon. When the tenon shrinks, instead of breaking the important glue bond around the tenon, a harmless crack appears next to the wedge. So now, whenever I glue in a wedge, I am careful to put glue only on one side of the wedge (plenty to hold the wedge in place). The unglued side of the wedge is free to open and close as the humidity changes, a far superior result to the joint failing!
So, save some glue and make a better joint.

Sunday, February 25, 2007

Gerry's Chair

Well, after about 65 hours, Gerry finished his chair and is racing the bad weather back to Virginia. I had a great time working with him and look forward to his return next year. Look for him in craft shows around Williamsburg, VA., he'll be the guy with the best in show award.

Saturday, February 24, 2007

Hide Glue 1-2-3

I guess the first question is where to get it! I like to know the gram strength of my glue, which tells me about the amount of water to add, the set time and the strength. Gram strength is a measurement taken when squeezing the glue in its gelled form. The higher the gram strength, the stronger the glue, the more water necessary to get the right consistency. I buy my glue from Eugene Thordhal at Bjorn Industries. He is an amazing expert and kind enough to give solid advice. He is also the only person that sells reasonable amounts (5lbs and up) of various gram strengths. The glue arrives in a granular form that will last indefinitely in an airtight bag.
I prefer 192 and 251 gram strength. These are in the middle range and appropriate for woodworking. When I want more open time I use 192 and when I am concerned about strength I use the 251. To extend the open working time of both glues I add 20% urea, by weight. The urea is availible as fertilizer at your local nursery. I have been told all sorts of ways to mix the glue. Now I simply add cold water to the glue and urea and wait about an hour or more. Then I put the mixture, in a plastic cup, in my Sunshine water pot (about $15, no expensive pot needed) set on the lowest setting and wait for the glue to go liquid. Never heat the glue above 140 degrees, it degrades the strength. The measurements that I use for enough glue to make a chair are
1 Tbs. glue
2 Tbs. water
1/4 tsp. urea
This makes a consistency like paint and should have a long open working time (3-4 minutes at 68 degrees air temp). I keep the glue warm when I need it and let it cool to a gel when I'm done. During winter, my shop is cool enough to leave it unrefrigerated when not in use. It is like food, it can spoil, so the fridge is a good place to store it once mixed.
Obviously, speed during glue up and the air temperature will affect open time. If the glue starts to gel up on the wood before you put it together, simply heat it with a heat gun and apply some fresh glue. It takes a little getting used to and gluing the undercarraige, where one joint can be glued at a time, is a good place to start. The joint must be assembled before the glue gels and then left to cure. Like sweating a copper joint, any stress after the joint is assembled can disturb the bond. A good introduction to hide glue is to use Old Brown Glue from Patrick Edwards. It is a liquid hide glue and comes bottled. Because of the shelf life, I recommend getting a small bottle. This is a basic introduction, like any tool, I believe that there is always more to learn to get better results. There is a lot of good info on hide glue if you google it. Always make a sample joint or two before relying on any glue or new mixing process. Good luck

Friday, February 23, 2007

Why Hide Glue?

The first question has to be "What are you gluing?" I make my chairs to hold tight without glue. Using bone dry tenons and air dried mortises, as well as tight joints ensure that the glue that I choose is a backup. No glue can glue a loose joint, except epoxy, and I'll touch on its limitations.
The next question has to be "why hide glue?". I use hot hide glue for a number of reasons.
The main reason that I use hide glue is that it is infinitely repairable. I give a lifetime structural guarantee on all of my work. Imagine one loose joint amidst the 20 or so joints in the top of a chair. Hide glue is the only glue that can reglue a joint (made with hide glue). Simply add a little steam or hot water to the joint and then some fresh glue. Any other glue would require disassembling the joint, and chair, scraping all the glue off, dealing with a now too small tenon and regluing, the entire chair! Perhaps epoxy could work but it doesn't have the 2000 year track record of hide glue and the only way to repair epoxy is to stuff more epoxy in the joint. And adding epoxy doesn't redesolve the old epoxy so I am not comfortable calling it repairable. All of those revered antiques were made with hide glue, and have been maintained with it through the ages.
Reason 2 is that I use hide glue is the strength. Unlike bottled glues, I can use various strengths of hide glue and never have to worry about cold creep (when white or yellow glued joints shift in time because they never fully harden). The different gram strengths availible can offer longer open times or greater holding strength. I have done many samples and have been amazed to see a 3/4" thick piece of white oak, edge glued, shatter, not on the glue line, or near the glue line but 1/4" from the glue line.
Reason 3 is that dry hide glue that I mix myself (a lot easier that you think) has an infinite shelf life. Bottles of premade glues degrade during their life. Is the last chair from a bottled glued as well as the first?
Reason 4 that I use hide glue is that it allows very tight joints to slide together without seizing. Yellow glue takes an instant bond in a tight joint and can sieze it before it is driven home. Hide glue acts almost like a lubricant until it gels.
Reason 5 that I use hide glue is that it has doesn't require the clamping pressure that white or yellow glues do. Instrument makers often use it to glue braces to the inside of violins etc... Just put glue on the brace and hold it in place until the glue cools.
Reason 6 that I use hide glue is the hot water clean up and interaction with finishes. Even dried hide glue can be dissolved with hot water, making scraping and sanding unnecessary.
There are many things that should be glued with other glues. I have found that hide glue is the simplest and best way for me to make a chair. I know that this is a contentious issue and that my opinions are my own. It is through much experimentation that I have settled on my current method. I will give details about mixing and using hot hide glue tomorrow.

Good Morning

I couldn't resist taking this photo as I walked out to start the fire in the shop this morning. You can see my homemade maple syrup rig buried in the snow. It was actually warm enough a couple of days ago for the sap to run. I can't wait to watch the sunrise while boiling down the syrup. I am having a great time with this blog and have been coming up with all sorts of topics. Soon I'll be talking about specific sharpening techniques, chair design, hide glue, drilling, and shaving, to name a few. Your input is essential to me as I try to guage how specific to be. I'd better get back out there and stoke the fire, Gerry will be here soon.

Thursday, February 22, 2007

Guest Blogger Gerry Felix pt.2

Spent the majority of the day on the lathe, concentrating on the skew and spindle gouge. Was able to occasionally make skew passes that were clean, requiring no sanding. Beads and coves were OK, as well.
Reminded that sharpening is equally important as application. Mistakes are very often caused by dull turning tools rather than technique. We made many trips to the water stones to keep clean edges on the skew chisels. Rocker assembly soon the pieces are about finished.

A Good Craftsman Blames His Tools

Of course the adage states that it is a poor craftsman that blames his tools. The more that I work with handtools and teach the more that I think this is false. So many of the problems and also of the improvements that I find are due to a better tuning of the tools that I am using. As I ask more of them, finer surfaces and faster results, they seem to require more attention. Using a tool that isn't sharp is like driving a perfect car that happens to have flat tires. All of the other components being correct don't help if where the rubber meets pavement is flat. Often with students, I'll introduce them to a tool that isn't perfectly tuned to acquaint them with it and then we tune it together. The difference between the before and after says it all.
Some tools, such as the oft dreaded skew chisel, don't do the intended job at all unless tuned properly. The key to the skew is that the angle at which the two sides of the bevel meet cannot have any rounding at all. It must be flat, or hollow ground right up to the edge. Now I know that a slightly rounded edge (not to be confused with a curve along the edge) will cut, but it won't cut as cleanly and is much more difficult to control. This tiny difference counts dramatically in the performance of the tool, especially if your goal is to eliminate sanding. So my adage is that a good craftsman blames his tool, and then goes and tunes it.

Wednesday, February 21, 2007

Guest Blogger Gerry Felix

Just finished day 2 of the rocking chair class with Peter. Got a slow start, managing to get stuck in a ditch before we even started. But Pete picked me up, arranged for a tow truck and we were off and running.
Spindles are drying, comb back carved and bent, arm bent, seat carved, so we're back on schedule. As it should be; it's my second time around with Pete. Amazing how much one forgets because he thinks he'll remember. I'm relearning much, and have the added benefit of observing Pete working on his signature rod-backs.
So here we go on day 3, turning with a special emphasis on the skew, my favorite subject.

Tuesday, February 20, 2007

Planing Tips

This morning, Gerry and I were talking about handplaning and I showed him a technique that I thought worth sharing. There is really only one way to push a handplane, all of the pressure on the front at the beginning of the stroke, even pressure in the middle and pressure down on the back of the plane at the end of the stroke. This is easy to say and hard to do. In the photo you can see Gerry demonstrating the way that I've found to practice. Take a small block of wood with a flat end, set the plane so that the blade is completely retracted (you don't want to cut in this exercise) and try to pass the plane across the small end without it tilting off at the beginning or end of the stroke. About ten passes later you should get the idea. Now it's up to you to use this same stroke whenever planing. There is one major problem that occurs, as humans with a sharp tool in our hands, we want to see the tool cut wood. So we abandon the proper technique in order to take a slice. It's more important to cut the right wood. Trust the plane and a proper technique, the wood will cut where it is supposed to.

Monday, February 19, 2007

A visit from Gerry Felix

This week I have the pleasure of teaching Gerry Felix how to make a combback rocker. Gerry came last year and made a continuous arm. Last year, he had the good fortune of being here during maple syrup season. Working with a student who has been making and selling chairs for a year now is a very different experience for me. The questions are specific and the skills come a bit easier. I'll be updating his progress all week.
I have one more thing to say about my recent Where to start? Where to stop? post. My wife, Sue has been learning to make jewelry. Watching and encouraging her has reminded me of the difficulty we all face when we take on new skills. Looking at her first work, I reminded her that the things that she learned making it would ensure that she could never make another one just like it. As makers, we will always be looking to improve, but should learn to appreciate the work in front of us as a friendly marker along the way.

Sunday, February 18, 2007

Where to Start? Where to Stop?

I had a visit from a young man who is aspiring to be a chairmaker. He was trying to weed his way through all of the information that he's been compiling and figure outwhere he should focus his attention. I have great sympathy for this position, not only have I been there, but it is a place that I find myself in constantly. Where to begin?
In woodworking and with my students I have a simple answer, sharpening. There is a lot of information out there about sharpening, in fact, too much. This is where the question turns from Where to start? to Where to stop?
When is the tool sharp? I have a simple test that I like to use. Any tool that will shave the end grain of a soft pine board and leave a smooth waxy surface is sharp. The soft pine will tear up with anything remotely dull. Why this test? By cutting the pine, versus shaving hair etc.. I can see the condition of the entire edge, not just that it has sharp areas but is completely sharp. To me this is vital because much of the finish surfaces of my work is straight from the blade, no sanding. Also, a sharp tool is a joy to use and in many instances, the only one that works.
When I was trying to figure out Where to start?, I got some woodworking magazines and read that the handplane could take feathery shavings and leave a perfect surface. Great, so I went to the hardware store, bought a plane, went home, assembled it and pushed it across a beautiful piece of cherry. Of course I mangled the surface. My inspiration was as damaged as the cherry. What they don't tell you on the box is that planes, or any handtool, are sold as kits. It is up to you to tune and sharpen the tool. Some expensive tools need very little tuning while cheaper ones may require hours.
I now know that even a screwdriver can take feathery shavings and leave a perfect surface, if it's sharp.
So after watching me work in the shop for a couple of hours, my visitor left with a list of books and the notion that he needs to learn to sharpen. I am adding the list of books to the blog.

Friday, February 16, 2007

Life in the new Shop

After years of working in my basement shop, this winter in the new barn has been a joy. One of the greatest advantages of greenwoodworking and chairmaking is the minimal tooling and space required. This was great when I was starting out but after a while, the makeshift surroundings started to wear thin. So last fall I cut the joinery (with help from my friends and a fantastic chain mortiser) and had an old fashioned barnraising. You can check out the raising at My barnraising page. The new shop has plenty of space and light and has been no trouble to keep warm with the woodstove. Something feels perfect when I clean the shop of scraps and heat it at the same time. My heartfelt thanks goes out to the countless folks who worked so hard to help make my new shop a reality.

Wednesday, February 14, 2007

Chair Notes, an introduction

Hardly a day goes by in my shop when I don't learn something. I like to think of my shop as a laboratory for finding elegant solutions to the problems posed by chairmaking. To me, chairmaking is the interaction of the human form with the potential of wood as a material. I think the potential for exploration is endless. A chair must be beautiful from 360 degrees, durable, and comfortable, a tall order. I've decided to create this forum to share information and inspiration. Teaching has turned out to be one of the great joys of my chairmaking experience. It is a simple thing to share something that you're passionate about. My production schedule allows me to teach about 20 students a year in my one on one seminars, but this seems to merely scratch the surface for the desire for good information. That being said, there a many ways to skin a cat and I look forward to learning from you and hearing your ideas. I am diligent in my desire to find the best techniques but am fully aware that we each have our own priorities and hope that mine will be of help or interest to you. I am excited to share my experience with you.