Saturday, April 7, 2007

The False Miter

This is a sequence of photos that I took while carving a false miter joint on a rodback. The wood is cherry. The large block in this image is a remnant of the lathe that I rough trimmed on the bandsaw. Most of the shaping is done with a full sized drawknife. It takes a great deal of focus because there are few reference points to tell me where to stop, just careful observation of the shape as it forms.

Once the major shape is roughed in, I use carving tools and spokeshaves to make the shape flow into the rounds that lead into it. A cut with a V shaped carving to makes the false miter appear.

I had an interesting discussion with Chris Durbin (I'll be posting photos of his excellent work later) about risk in craftsmanship. One of the great advantage of hand tools is the immediacy and intensity of involvement that they offer, but it comes at a price. There is a learning curve and the potential for ruining the workpiece is often just one move away. This can force us to retreat to the safety of taking tiny cuts which is inefficient or even worse, stopping before achieving our goals for fear of ruining a piece. A painting mentor of mine used to encourage me to ruin my work rather than stop short. He said that by going past the line of a "good" painting and into a disaster, at least I'd learn where that line was. Alway stopping short leaves us holding our breath, working in fear. It is a difficult practice, one that may send one running for the certainty of a tablesaw and some sandpaper. I have messed up a lot of work. I'd hate to see the pile of chewed up turnings that I've made. But imagine an infant, unwilling to give up the stability of four limbs on the ground for two. Then think of the boldness of lifting one of the two off of the ground! We all know where this goes. So if, on occasion, the piece of wood in front of you has to be sacrificed, rest assured, it is not in vain, the next piece to take it's place will benefit in the hands of a more learned craftsman.


greg said...

I was admiring a birdcage chair (I think it was made by Curtis Buchanan)at Dave Sawyer's, and I asked Dave why the large part of the turning left for carving duckbill joint wasn't left on the post instead of the crest rail. It seems that mechanically this would be the stronger joint considering that chairs are often picked up by the crest rail. I suppose the advantage of doing the way everyone does it is that it makes carving the joint easier. Dave's answer was that I should try it.

I haven't gotten around to making one yet, though. I have to convince someone that they want me to make them some first; I haven't had the luxury of making a chair that I feel like making in a long time.

Peter Galbert said...

I think that the having the carving as a part of the crest is both easier to carve and stronger. The spindles that pass through the crest are wedged and keep the crest firmly in place. Also, when you sit in the chair, your weight puts a force that acts laterally against the tenon. If the tenon was on the crest, your weight could act to pull the tenon out of the mortise. The carving is easier because the post side of the joint can be shaved upward, I think some trials would show this. The difficulty of this joint shouldn't be underestimated, it takes great care and patience, but of course, with practice it is quite attainable. All that said, I think that Dave has the right idea, try it, there are no sacred cows here.

Frosty said...

I like your rodback chairs.

Your 'false miter' is commonly known (in masonry and woodworking terms) as a mason's mitre. This so-called mitre is used by masons around windows and doors and was used on 17th and 18th century English and European (and I suspect American too) oak wall panelling and panelled furniture.

The crest rail of English chairs sits above the rear uprights/legs whereas the French equivalent sits between the uprights/legs. It's quite apparent in 18th and 19th century English and French parlour chairs and, given the prolific occurrence of them on both sides of the English Channel, is a primary indicator when identifying them.

I would agree that having the crest rail atop the sides is the stronger method.