Register controls

The on/off positions of the registers are controlled by capstan screws at the left and right sides of the harpsichord. Here is the set located at the cheek:


The thickness of the brown block is the same as that of the jackrail supports, which ensures the screw heads won't be blocked by the supports.

By inserting a thin rod into the holes, the screws can be turned in and out. The register ends butt up against them, controlling their sideways motion.

To locate these screws I had to cut down the registers, which were still a bit too long, and this meant I had to have a fair idea of where the on and off positions would be. I determined this by progressively trimming the register ends and trying my prototype jacks in various slots after each cut.

Shifting the registers on and off is controlled by this pair of register levers on the spine side of the instrument:


The handles are brass lamp finials, used to screw down lampshades in a decorative manner. They fit into two brass bars, which I drilled for the necessary screw sizes and polished. At the far end, the registers were drilled for #8-32 machine screws which self-tapped their holes as they were screwed in.

Since the jacks will face in opposite directions, the on and off motions for the registers are opposed. Moving both levers in the same direction silences one stop and turns on the other, while pinching the levers together turns both on.