Baseboard: Selecting boards

In many harpsichords, the case sides are a major structural component made early on, and the bottom gets nailed to them much later. The casework of such instruments forms a rim that other components are attached to, so the boards it is made of must be strong and fairly thick. The bottom, or baseboard, of an Italianate instrument (this category includes some south German instruments made along the same lines) is, on the other hand, a major structural component. Various items are attached to the bottom to make a kind of inner frame, and thin case sides are glued all around this frame.

My instrument will have its bottom from that western red cedar I recently bought. A&M resawed it to slightly over 3/4" and our planing extravaganza got everything down to around 5/8" thick. This is thicker than some historical Italianate bottoms (only 1/2" on some instruments), but my research suggests that western red cedar isn't as stiff as other softwoods, so a bit extra can't hurt. It's pretty light material, and is said to be quite stable.

To cut the boards to length, I simply placed the first board on the left edge of the drawing and looked to see how much of the drawing was left exposed. Each succeeding board was then measured from the front edge of the instrument to the bentside line on the drawing where it disappeared under the existing board, cut to that size plus about 4" extra for safety, and placed right next to the previous board.

The process continued until the outline of the instrument was completely concealed.

To make sure I would have enough material, I estimated the area of the baseboard by calculating it as a triangle sitting atop a rectangle. This area was divided by the width of the boards I could get and translated into a linear measurement, as if of one enormously long board. Then it was simply a question of getting enough individual boards to sum up to that one imaginary mega-board. The only thing to be careful of was to ensure that the leftmost boards were the full length of the instrument (about 92").