Monday, February 16, 2009

Starting to get shafted

Back to conjecturing...

As previously noted we're faced with drawing conclusions from period iconography of horse carts to design our dog-cart. The Lutrell Psalter has several representations of wagons, but all of them have straight shafts. Should we not use straight shafts as well?

There are what I believe are several logical reasons not to.

First, let's be honest, the curved shafts are more aesthetically pleasing, and if I'm going to all this work I want something that looks cool. What can I say.

Second, in line with the conceit that this cart would have been built at an on-site workshop of a monastery or latifundia it's not unreasonable to assume bent poles. If we are to keep the bed level, and not spill our goods on the ground we cannot use straight shafts. They would require larger wheels, with a consequent increase in weight. Remember, we're not looking at a cart to be pulled by a heavy draft horse or ox, but by a dog. The load is limited. Every ounce more in cart weight is an ounce less of potential useful load. The cart would be made as light as possible to make the load as great as possible.

Third, the craftsmen of such an estate would have had ready access to coppice. It took me only a few minutes walking around to find two suitable poles. For my full-size Djebjerg Wagon project I have several pieces of very complex curved natural growth seasoning. It took me about an hour wandering through the woods to find the two trees I used. If it's this easy in 21st century mid-America to find suitably curved standing wood, how much easier must it have been in a more heavily forested and coppiced medieval Europe. Additionally, our hypothetical craftsman would not have been under a deadline--he could have bent trees and allowed them to grow to shape as was done for boat building.

So I think it's not inconceivable our craftsman would have elected to use smaller, sturdier, lighter wheels, and use poles that curved to a useful height and distance.

Unfortunately, finding perfect poles is not as easy as finding fairly good ones. To get what we need is going to require more than careful shaping with the drawknife. Thus we'll need to steam bend the poles to get the desired compound curves. We know that steam bending was done in period by furniture makers and boat builders so the technique is appropriate. And I don't think it's stretching our conjecture too far to posit that our craftsman would have used it rather than spend large amounts of time searching for just the two perfect pieces of wood.

Today I cut the second pole and shaped it as with the first one. Since it didn't match exactly with the old one we'll correct the differences with steam.

Right now the two poles are clamped together hand bent to roughly the intended shape. This is as much as could be achieved with hand pressure, clamps, and carving. The back end is clamped flat to the table and some curvature induced with blocks and weights. The tips of the poles are about eight inches higher than the back ends. We can fiddle with the axletree some, but this puts our axle about 11" - 12" high and the poles about 19" high, a good hieght for a drafting dog.

Clamping like this helps the wood develop a "set" while it dries awaiting bending. They will stay clamped like this while the clamping jig is constructed and the steam box is assembled from an old turkey fryer and some pvc and copper pipe.

Tomorrow we steam!


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