Pachyderm

Maybe its the scale or the lovely gray of the weathered beams, but the finished shed frame reminds me of an elephant. In one of the books that I read to learn timberframing, they used the analogy of a timberframe supporting the building like a skeleton, where as modern framing is a rigid skin. One look at this says it all.





There are some similarities that I've come to enjoy between timberframing methods and chairmaking. I spent the last week teaching Ernie Palmieri to make a continuous arm. Ernie has been a woodworker longer than I've been alive. He's built everything from houses to fine furniture (including a rocker that he completed before taking my class). We spent a lot of time laughing as Ernie learned some of the more "organic" methods that can be employed in making chairs from trees. It's a whole different type of precision. He would laugh whenever I said that we were going to "eyeball" the work. On a couple of occasions I reminded him that squares and tape measures are read by "eyeballs" as well!

The great departure from standard woodworking, by which I mean the kind where parts can be made from a plan and then be interchanged in assembly, is that in a chair, you build to the chair, not the plan. Pieces become assigned locations and the process must take the actual shape of the existing pieces into account to determine the next step.

In timberframing, the beams are not cut to standard dimensions. To my sawyer, a quarter inch here and a half inch there are pretty much standard. The beauty of the timberframe process, is that the layout of the joints enables the builder to work beyond standardization, which I find to be quite graceful.



Here is a beam mortised into a post. The concept is the same as in woodworking, but with one difference. Instead of planing the post to a standard size, I simply notch the shoulder of the tenon into the post far enough to leave a standard 4 inch thick piece. It is by measuring from the depth of this notch that I can determine the length of the beam. A four inch post on both sides adds to eight inches, subtract from the overall length desired for the structure (twelve feet) and I know to cut the tenon shoulders eleven feet and four inches apart. With this creation of references, I soon came to understand how an entire structure could be made using logs that were flattened and squared on only two sides. How's that for "organic"!





Here is the one part of creating the layout that may take some real headscratching before diving in. The cross bracing is meant to control wracking by preventing compression. Often, they weren't even pegged. With all of the extra wood hanging around on the posts and beams (not to mention the braces themselves), finding the correct references to create the triangle and determine the length of the hypotenuse can be a challenge. I laid out string to show the actual geometry. You can see that based on the references used, there is a logic. I found a book by Jack Sobon to be incredibly helpful in learning to get exact dimensions from inexact timbers. If it weren't for the intense physicality of the process, I could see being happy as a timberframer, it is a great challenge, but I prefer being able to lift my product easily over my head. So chairs it is...

Big Tenons

Here is the process for cutting the tenons for my timberframe shed. I used a combination of hemlock and white pine. Basically, my choices were based on whatever I had leftover from building my workshop. When I built the workshop, I tried to use the pine for posts (which mostly get mortises) and the hemlock for beams (mostly tenoned). The pine is much easier to cut mortises into and the hemlock offers more strength for beams.



Here is my homemade marking gauge. The center spur was helpful when I used to drill out my mortises with a 2 inch forstner bit.





Here I have used my circular saw (my first powertool, now approaching its 20th year of service!) to kerf to the proper depth around the tenon.
After knocking off the waste, I cleaned the tenon up with my slick (think large chisel that cuts like a drawknife). This was a particularly gnarly piece of hemlock and didn't give the prettiest results, but they'll be around long after I'm gone.



Here is a view from the top of the tenon.



With the help of my friends Bill and Rich, I erected the structure the other day. There is something amazing about seeing the whole thing raised in an hour or so. While working on the frame, I kept thinking, "this will be the last timberframe I do" but once it was up, the simplicity and grace of the frame has me looking forward to the next one. Whenever building with mortise and tenons in the standard table and cabinet size, I suppose we believe in their utility because we are told to. How often are we around to see the true benefits of the extra effort to create solid joinery? But in a timberframe, there it is, push with all your might and the joints answer back with a strength that resounds. So much of woodworking seems to be about pursuing the expectations of strength and quality that I cobble together from a myriad of influences, I find that the simple strength of the timberframe is an answer in itself.

Finis

Here is the finished cherry, butternut and hickory rocker that I have been building. The design and construction had a lot of interesting lessons that I plan to take forward into new work.



Here is where the design of the back began. I used my student Stacy to test out the curve of the spindles, which I cut into a 4 inch thick chunk of pine left over from my timberframing (I will get back to that soon!). By notching the back of a dummy seat and clamping the rig to my shave horse, I was able to adjust both the curvature of the bend and the relationship between the back and the seat. Also, by slipping a wedge under the seat, I was able to adjust the tilt of the chair. It worked out great and I based all of my curves and angles on it.



Here is the bending jig that I used to bend 8 spindles (one extra!). It worked out nicely.




Here are some more images of the finished chair. It is very comfortable. I had a variety of folks sit in it at the Narrowsburg Riverfest on Sunday and got uniformly positive reviews. I plan to delve even further into the physics of rocking and comfort on the next chair. I also played with the spread and splay of the front legs to balance out the large and shapely top.




My next rocker will be all white oak with a butternut seat. I plan to fume the whole finished piece in ammonia to darken the oak. I've done this before on tables and small kitchen pieces and love the results. I am also adjusting the design to make it possible to finish nearly all of the surfaces with a spokeshave, I have seen too much of my old nemesis sandpaper lately. Next week brings a new student into the shop, so I'd better get out there and get my personal fussing overwith!