Sunday, May 20, 2018

Curtis Buchanan Sack Back Day 1

I'm honored to be in Jonesborough, Tennessee, USA starting Day 1 of Curtis Buchanan's Sackback Windsor chair class. I've always wanted to build furniture from freshly felled timber, for a variety of reasons. Nothing quite compares to working with wood 'in the green' as they say. it carves much easier, and the tools involved are so much fun. you learn about cleaving wood directly from a log, and then riving it into smaller pieces that are then taken directly to the shave horse and worked into things like spindles, or arm rests.

In this style of woodworking, the wood is alive. the grain has it's own direction and my main challenge as a novice is to let the feedback of the edge flowing with the grain of the wood dictate what direction to run.

The class consists of 3 students. There is no way to put in words what Mark, Rob and I have been learning within any moving 30 minute window while here. I was too concentrated on watching and doing and note taking to get a lot of photos in. We hit the ground running, and go right into the splitting!

Here Curtis is showing us some nice white oak that had been out in the air too long to be viable and had started to have some surface checking along the radial plane where oak tends to split quite easily. I had originally mentioned honeycombing as a similar thing, but this is an entirely different effect due to improper kiln drying.internal splits forming along the radial plane. i've heard of something called "honeycombing" and have seen this sort of effect in wood improperly kiln dried.

In our class, we start early and get really clear on the basics of wood structure. When talking about splitting wood along it's grain, we use two important terms: Radial plane, and Tangential Plane. Here's a good picture of what Curtis is describing.

Curtis' mandatory syllabus includes Understanding Wood - By R. Bruce Hoadley, which goes into great detail about the physiology of wood, and what it's doing especially in response to changes in humidity, grain direction, etc. Curtis' lays it plain as day that you can't really be a proficient woodworker unless you understand how wood behaves. It needn't be a mystery.

Now today, we're working on the spindles for the chairs, all day. It starts from chunks of white oak that Curtis had reserved for classes. It's particularly good wood as most of us students are going to have enough challenges just getting something approaching useful in a project, having tricky grain issues are beyond folks like me at this point!

When you are breaking down a log, it's done in phases. You start with wedges tapped in with a lump hammer, and this process is called cleaving.

Once you've cleaved your oak into manageble sizes, the next step is to rive it using a froe. Now, as curtis says: "knowledge takes ten generations to build, and only one to loose." The Froe is a perfect example. It's an "L" shaped tool used to deliver very precise instructions to the wood on how to split.

Curtis is a self described "Froe Evangelist", and there's good reasoning behind flying this flag: no other tool can do what a froe can. A froe is excellent at guiding the split line between two sections of wood. Frequently what can happen when splitting is that the crack will get ahead of where the grain naturally runs, but with a froe used in conjunction with a brake, you can guide the split and more easily rive out even pieces. the 2x12's you see in the background below connected by 2 offset dowels are what is called the brake.

Here, he's initiated a split with his froe and has it supported in the brake. You use the lever action of the handle to guide the split, and you press downward when in this position. So you orient the side of the split that is "heavier" downward. The heavier side is the piece of wood that the split appears to run away from. it's fascinating. I could take pretty much the rest of my life just riving out billets like this and never grow bored.

Curtis relayed the use of froes primarily in the construction of roofing shingles (roof boards) in this part of the United States. A terrible terrible hail storm in the early 20th century destroyed so many roofs in the region, that during reconstruction, tin roofs became the norm, and the craft of using a froe ebbed away, lost from one generation to the next. However, the tool's application has been invigorated by chair makers needing this kind of tool to efficiently process wood for chairs.

the rest of the day was devoted to incrementally refining spindles from the rived pieces. It's too complicated to put into words here, but the joys of using a foot operated shaving horse to hold the wood, shaping with a razor sharp draw knife, and all the time the increasing scent of white oak bringing me back to the barriques holding Napa and Sonoma Valley wines is irrefutable. it's intoxicating. i didn't want to leave and was overcome by my very senses.

If I were to relay one message about the technique it would be about "maintaining your references". First you ahve to find the tangential and radial plane on two faces of your spindle blank. It requries letting go, and using the force, Luke. Do a few thousand and it will be natural. For us it took a while. You then create tapers along the same facets, and then incrementally form an octagonal cross section along the entire length of the spindle. This then goes into a kiln overnight for spoke shave fun tomorrow.

I am overjoyed to be here. I remember a few good things about my life back home, like sarah, and our two cats and my garage.

I'm happily lost in the process.

Ok, this is one of the great pleasures about being here, I have to tell this little story, there were many such as this today

Curtis has a few egg hens on his property, and they live an idyllic life with plenty of room to scratch, but a new rhode island red arrived on the scene which had the others clucking and inspired to test their wings, jumping over the fence. I relayed a story from my youth about having similar problems with our bard rocks and that, as kids, one of our chores were to clip their wing feathers (an inch or so from proximal end) to prevent them from being able to fly. As luck would have it, one of the students, Rob, is a Nevada veterinarian, so we had an impromptu remedial session to keep the hens in the coop.


  1. What an unbelievable opportunity. I'm assuming you're from Oakland, CA, not some other Oakland. I've wondered if we Bay Area people can get green white oak that can be used like Curtis does. Have you thought about that? Any idea where?

  2. hey matt! yeah, i'm in oakland, ca. we should connect! i have seen your blog on the unplugged aggregator. No, we will never find oak like this on our side of the continental divide. I think we just need to find what is available and make something respectful of it.

    THere's another student from Nevada who's kind of in the same boat as us. White Oak is just not gonna be available for us. I read somewhere that you can't be a woodworker unless you know how to work with what's available in your back yard. And i have to agree that this is a very wise statement. That said, mabye there is something amenable to steam bending that nobody knows about yet in the bay area?