Esoteric Information

I have been in the process of putting together a new centerboard trunk, 10 feet long, constructed with splined sideboards bedded in white lead paste the way it was done by Goudy and Steven’s in 1930. There are some interesting considerations. One of which is choice of wood and how tight to cut the splines so they are neither too tight nor too loose after they swell. As matter of curiosity I put a spline in a glass of water to see at what rate and how much it would expand (coefficient of expansion). The wood is Angelique. When cutting the spline slot with a dado blade, a 0.500 inch wide dado left a slot width of 0.478 inches (on average) since the wood tends to compress and bounce back due to its hardness. Measurements are made with a digital caliper to 0.001 +/- 0.0005 inches. I ran the splines through the planer and ended them up between 0.473-0.470 inches in thickness. After three days in water they have swollen to 0.488-0.490 inches. This should create a good water tight joint without overstressing the wood from excessive swell. This does not consider additional tightness due to inward pinching of the slot as it swells. If someone is rebuilding a trunk, you might consider evaluating the amount of swell of the wood before you make the design decision on the thickness and height of the spline. I did it in the reverse order (quantitative measurements after the wood had been cut), but on second thought, would have done it the other way around.