Every year, my brake gets a little uglier. Usually it breaks through abuse, the freeze, thaw cycle and the life outdoors, but I scab on some old scrap of wood and keep it going, always promising myself that soon I'll build another. Yesterday I had an idea that might just spur me on to really do it.
After giving my talk about splitting, you know, that one about how when both sides of a split piece deflect the same amount, the split always runs straight, I had an idea. Whenever I come up with something that I haven't seen or tried, I try to find the shortest distance to the "Proof of Concept". I did it with my caliper (the first one used an old plane blade and some rubberbands) and I do it with my chairs.
So while looking at the brake, it dawned on me how easy it would be to hook up a lever to increase the leverage on the larger side to get the equal deflection while splitting. My student this week was game so we took a few minutes and rigged up this fine looking contraption.
Here is Peter (there are a strange number of Peters in woodworking) applying the necessary pressure and splitting off a small crest for his comb back. It worked like a charm, too well actually, as he was able to make the split run into the larger piece!
Most of the time when splitting, we strive to split equal sized parts because even deflection is relatively easily achieved, but necessity means that we must often split off a third of a chunk, and this is where the extra leverage comes in handy.
The biggest problem with the "Proof of Concept" moment, is that I am often so enthralled by the crude simplicity of the thing, that I'll use it that way for years!
Here is Dan finishing up his triple back a few weeks ago. I really like this chair and hope to own one myself someday!