Bar Stool Prototype

Recently finished up the walnut prototype of the counter height bar stool I began designing while co-teaching the chair design workshop with Jeff Miller at the Center for Furniture Craftsmanship this past October. The minimal structure and clean kinked lines was inspired by a students chair design. The miters joining up in the back of the stool to give the "birdsmouth" look came about as a bit of an accident, a pretty happy accident perhaps going back to my days sharing studio space with Brian Reid.

Already there are some changes I think I would make in the next reiteration. For one I think I would like to pull the foot of the back leg in a some, the stance is a little too extreme for my taste. A wise chair maker once told me, "every chair you ever build is a prototype, you will always see improvements you can make no matter how many of them you have made." With that said I would like to welcome the counter height bar stool no. 3 to the family and look forward to testing this one out and developing it as time goes on.

The Indestructible Miter

Before you get into this, I am sorry, this post is long, it may or may not make a lot of sense, and I am sure a lot of people would argue with what I have said. Carry on. Indestructible miter. A bold claim I know. Indestructible and miter are words that do not often go together. The miter opened up, this mitre won't close, why did I choose to use these damn miters, all a lot more common to hear.

But bear (bare?) with me here, what you are about to see below is an adapted version of a joint that was introduced to me as "the indestructible miter." Or if you would like to take it down a few notches on the "awesome scale" the plywood L-tenon. It is exactly as it sounds. Plywood and indestructible are again two words we are not used to hearing together, but it is the perfect material for an L-Tenon.

Why you may be asking? Alternating grain direction for maximum strength. It is really just that simple. Miters are difficult to join because of the amount of end grain in the joint (end grain has no glue strength). This is why typically we cut keys or splines in a miter joint is to gain some "face grain glue surface."

But isn't half of plywood end grain? Sounds like you are going against your own advice....

You got me, it's true, but the other half is perfect face grain to face grain glue surface. And the end grain portion on the one side of the miter is the face grain on the other part of the board. Tricky no?

But there's another part to this equation. Keys / splines and most other miter "joinery" has very little "depth" into the actual boards. This may be okay for little boxes, or a casepiece, but chairs are under stress, a lot of stress, and they need something a little more substantial. The "L-Tenons" allow me to route deep (in this case around 2") mortises into both parts.  What I end up with is a 2" worth of tenon (and a longer bit could get me more) into either side of the miter. Quite a bit of depth all things considered. Couple this with the alternating grain and you have a joint that is "indestructible," relatively speaking anyways.

This may be a lot to take in at this point, hopefully the pictures will clear it up some. For the record these are a bit of a variation on your standard "Plywood L-Tenon" as they are obtuse angles and canted as well. Testing as to the actual strength will commence once the stool is together. Stay tuned.

Drawing and Reality

So with the mock-up complete for Bar Stool No. 3 it was time to move on to a more detailed full scale drawing. Below is a drawing that the more I tried to simplify it the more complicated it appeared. The result was my brain getting pretty mushy and working on something else for the morning (see the post about dodecahedrons). In the end I needed to trust the angles and dimensions I had laid out and went to cutting the compound mitred frames that will make up this stool. The picture at the bottom is with the angles cut and pieces of tape wrapped around the outside of the miter to see how everything fits together. I should have been able to visualize this from my drawing (maybe?) but was pleasantly surprised when I began piecing the parts together and revealed the "double mitre" joint that will be visible from the back of the stool.

 

Chair Making at the Center For Furniture Craftsmanship

A couple months ago now I received a phone call from Peter Korn wondering if I would be interested in co-teaching a Chair Making class with Jeff Miller this September-October. Having been fortunate enough to have taught at the Center for Furniture Craftsmanship (CFC) the previous two summers I thought I was being "given the summer off." I was thrilled to be presented the opportunity and excitedly accepted the job offer.

It was a hectic two weeks but a helluva lot of fun. Seeing people starting to "get it" is a pretty remarkable thing to watch and even more rewarding when you played a part in getting them there. I had a great time teaching with Jeff Miller (check out his work and blog at www.furnituremaking.com) and learnt a lot from this chair making (and teaching) veteran. He was very encouraging to me as a teacher, I am still learning at this teaching gig so every bit of advice is helpful.

As for the students I couldn't have been more impressed with what they were able to accomplish in just two weeks. Coming from a wide array of backgrounds these 12 gentleman powered through what is arguably one of the hardest challenges in woodworking, the chair. Kudos to all of the students who made the class what it was, Jeff, Karl the awesome assistant and the CFC for hosting. Here's to good times and hopefully more to come.