Thursday, December 25, 2008

The Perch Stretchers

One of the persistent difficulties to working green wood is understanding its advantages and the processes that can exploit them. How wet? How dry? When do I shape it? It can be confusing to the newcomer.
This installment of the perch building process gives a great opportunity to clear up a few things about green wood. There are only a few reasons to work green wood, and if you take them into account, it should be pretty clear when and how to use it.

Number One: green wood splits and shaves along the fibers which allows for stronger, yet more flexible parts. This enables the thin turnings and solid bends.

Number Two: green wood cuts easily with handtools, enabling quick shaping without the need for powertools

Number Three: green wood is cheap and easily found, with the only drawback being that trees don't come in squared lumber. Of course, in green wood chairmaking, the parts rarely use the type of flat references that dried lumber provides

When using green wood and making process decisions, I ask myself which of these benefits is essential and which is merely helpful. In making the stretchers for this perch, I have tried to take advantage of the green wood advantages where possible and abandon them where the returns diminish.

There are a few options when making the stretchers for the perch.

One, I could have split the wood green, turned it green, dried it and then sized the tenons to the final dimension. This works fine and has the advantages of the strength of the split wood and the ease of cutting green wood. The drawback is the time it takes to dry down the piece and the need to dramatically reform the tenons before assembly.

Option two is to split the wood into billets, rough shape the stretcher, dry it down and then turn the entire piece once it's dried. Once again, the benefits of the green wood splitting and roughing help out and turning the final shape from a slightly oversize rough wouldn't be too difficult in the dried wood. Plus, I would be able to turn the tenon to the finished dimension at the same time that I turn the rest of the stretcher to shape.

Option three is to saw the blank from a dried piece (being careful to follow the fibers as though it was split), turn the stretcher (not as much fun in dried wood), dry it down, and then turn the tenons to final dimension. This is the option that I chose, mainly because the curly maple that I am using is already in the dried plank form. I am definitely sacrificing the ease of cutting for the benefits of speed in drying (the plank is already air dried) and the ability to cut close to finish dimensions.

Turning is different from shaving, in that the center axis of the turning can be easily made to follow the fibers through either splitting or sawing. I would never substitute sawing for shaving when making spindles or bends.

In the video, you'll see me turn the stretchers with the tenons oversized .025". This is because the wood is already dry and experience tells me that it won't shrink dramatically in the kiln. If the wood was green as in option 1 above, I would oversize the tenons .060" or .080".
I know that talking about thousandths of an inch can be a bit odd at first, but don't be intimidated, it's just a way of talking about the movement of the wood that is tough to describe accurately with out resorting to such tiny increments. My goal is always to turn the tenon to a size that will leave me trimming a minimal amount after drying. The goal is a final tenon of .625" or 5/8". When the piece comes out of the kiln, I want the dimensions of the tenon, as measured along the growth rings to be just a few thousandths oversize, for easy trimming to the final .625". It is of course easier to hit this mark if the wood is dry to begin with, which is why I tend to exercise option 2 above as my general practice.

To sum up, when deciding how and when to use green wood, the considerations of strength, ease of working, availability and flow of process, all come into play. If you find one factor that calls for the sacrifice of another, just make sure that it's one you can live with.

The posting on seat carving is coming up.

Monday, December 22, 2008

Reaming in the Legs

Here is a video of the reaming process. We finally get to see all this unusual geometry add up to a chair. It's important to have faith in the strange numbers and angles. I hope the video helps with this vital and difficult step.
Next I'll be covering measuring the stretchers and carving the seat. Any feedback about the info presented is helpful as I try to fill in the gaps.

Saturday, December 20, 2008

More Studio Shots

Here are the studio photos of the new Crested Rocker in fumed white oak and butternut.
I was excited to see it in the clean light of the photo studio.

I am looking forward to making a birdcage version of this chair, after I finish two of them in cherry that I am working on.

The instruction and video on reaming the legs and carving the seat is in the works.

Wednesday, December 17, 2008

Flattening and Drilling the Perch Seat

Here is the next installment in the perch making process. This video covers the hand flattening of the seat and the drilling for the legs. Of course you could use a planer and jointer to get this seat flat, but I use my handplanes, which only takes me a few minutes and teaches me a lot about the nature of the specific piece of wood that I'm using. I'm sure that there will be a few questions, so let me know if there something that I can clarify.

There are a few reasons that I drill the holes by eye. One is that the reaming process gives the opportunity to refine the angle of the hole, but most important to me is the speed and portability of the process. I could set up a drill press or some other semi-permanent rig, but then each time that I wished to change an angle I would have to adjust the jigging. Getting comfortable drilling by eye only takes a couple of practice holes and then you'll have a skill that you can take anywhere, at any angle, to any piece.

Monday, December 15, 2008

My Hero

Here is a very victorious Chairnotes covergirl after saving the lives of our chickens from a marauding hawk.

I was in the shop and Sue stopped in for her normal "I'm home, give me the dogs". As she was walking back to the house, I heard a crazy ruckus and the "drop everything" tone in her voice. I ran outside to see Sue, the dogs, a chicken and a massive hawk in a scene of total chaos. Sue charging the hawk, feathers flying, dogs going berserk, chickens running.

When the feathers settled, we counted one chicken hiding in the woodshed and three under the porch, but we have 5 chickens. Now, every story that I've ever heard the starts with "we had chickens" ends with a gruesome tale of blood and feathers, so I was prepared for the fact that we lost one. But then Sue remembered seeing one run past the door of the shop while we chatted, and sure enough, tucked under the far end of the workshop was number 5. So our gals hid the rest of the day, and perhaps we won't get our 3 eggs tomorrow (hey, it was traumatic for all of us), but for now, we are all safe in our houses.

I am working on a video to demonstrate the drilling technique that I use for the perch, after all, xmas is coming and we have a deadline!

Tuesday, December 9, 2008

The Perch Legs (Video)


Thanks for all the great feedback on the Perch posting. There have been a few topics brought up that are worth addressing. The seat material can be any wood that you care to carve. If you are using a softwood such as pine, I suggest using a 1 1/2" to 1 3/4" thick piece. If you are using a hardwood, you could go as thin as 1 1/4". The perch presents a great opportunity to become accustomed to drilling and reaming. Those who are new to the process, may benefit from creating a practice seat out of softwood (my first practice seat was 2X4's glued up!). This way the process will show it's quirks during the dry run.

As far as tools for the perch, I would suggest the 6 degree reamer from Elia Bizzarri at This is one of the last great woodworking bargains. The seat of the perch is only scooped out 5/8" at the deepest point. This is shallow enough to carve with a gouge and finish with a scraper, but if you are thinking of making more than one, I suggest the travisher that Elia sells (based on my design, but I have no stake in the business). It's a great tool and works beautifully. Perhaps your first perch sale or gift can cover these costs!

By its nature, the perch is a custom object. The goal is to tilt the sitter forward to encourage the lumbar curve to do its job. Each person will need a different height. The perch that I show is good for an average sized person (finally being average pays off!). I custom size them by putting books under the feet of the perch or the sitters feet until they are comfortable. One of the reader comments mentions a web page that describes the concept beautifully

As I mentioned before, the perch was a collaborative effort with input from Galen Cranz and Curtis Buchanan. Galen has literally written the book on chairs. The problem is that she finds that our entire relationship to chairs is faulty at best and unhealthy at worst. We live in a world designed to suit the work and dining surfaces we create, and let our bodies take up the slack! She inspires me to try to improve the design of my chairs to better suit the sitter. Her book is a must read.
The Chair: Rethinking Culture, Body, and Design (Hardcover)
by Galen Cranz (Author)

I hope these diagrams are easily read. These are just suggestions for the legs, if you are without a lathe, just shave the legs with a drawknife and round them with a spokeshave, don't let tools stop you!

Here is a video of the leg turning, I hope it helps

Monday, December 8, 2008

A Holiday Gift

I was considering posting the plans for my perch as a holiday gift to ChairNotes readers, but as with so many thoughts, time seemed to run short and other priorities took hold. But then someone contacted me the other day to request the plans, and put it right back at the top of the list.

I designed this perch with Galen Cranz and Curtis Buchanan a few years back when we were teaching a class on body conscious seating. Galen, an expert in The Alexander Technique and now head of the Architecture Department at UC Berkely, set the goals:

To use windsor technology to create a seat that would make sitting upright easier and encourage proper alignment of the vertebrae.

The perch does this by keeping the pelvis rolled forward, similar to when you are standing. This way, the natural spring S curve of the back is maintained.
I love watching people faces as they sit on the perch for the first time. It's near effortless and nothing like they expect.

This is also a great project to undertake as an introduction to windsors. The legs can be turned from dry wood, as long as it is straight grained, and the seat isn't deeply scooped, so you can forgo some of the coarser carving tools.
My one warning is that your friends and family will line up for theirs, so either be prepared to make a lot of them or keep it hidden when they are around!

Below is the pattern for the seat. I hope that you can make out the numbers. Obviously, the exact shape of the seat can vary a bit.

Perhaps the strangest part of the perch, especially to experienced chairmakers, will be that the legs all rake towards the front. The front leg is quite a bit shorter than the rear and causes the forward tilt in the seat. It tilts so far forward in fact, that the legs take on an even rake, both forward and back. I've drawn a quick sketch of the perch and then one next to it that shows the legs when the seat is resting horizontally. Odd isn't it! So take a moment to get used to it and start gathering materials.

I'll post the leg patterns next as well as a video of the turning process. Then I'll continue to post on it until it's done.

Tuesday, December 2, 2008

A Link Worth Following

I first met Brian Boggs about nine years ago at a 2 day seminar that he taught at Purchase College. I was still working in cabinet shops in NYC and was trying to make my way to chairmaking. I had John Alexanders book and plenty of woodworking experience, but the leap to green wood was still daunting. So I jumped at the opportunity to watch and listen to Brian.

The other day, I came across this 63 minute lecture that Brian gave recently at the Woodworking in America conference. I poured myself a cup of coffee and tuned out the rest of the world for a while.

As usual, Brian's intense pursuit of quality and understanding was an inspiration.
So do yourself a favor, check it out.

Brian Boggs at the Woodworking in America Conference