I thought I had this figured out, but… nope. Still don’t know how to do the balance pins.
What’s a balance pin? Well, it’s the main pivot point for the part of the piano that the key is directly attached to. In modern pianos, it’s a pin that goes vertically through the key, and the hole it sits in is elongated, front-to-back, wider at the top and narrower at the bottom, to accomodate the motion of the key.
A hole which is elongated and wedge shaped just isn’t going to fly in my shop, so I’ve been trying to figure out an alternative. Here’s where we’re at right now:
As you can see: I’ve got all the pieces for a full octave with a few extra on each side, and they sit nicely in the little text frame I’ve made. But those long levers just won’t sit still on the nails I’ve driving through the bottom frames. I think the answer might be to create a flanged hinge (like all the other moving parts have) but now that I’ve drilled holes into the bottoms of all those frames (and glued all those pieces together!) I don’t know if a flange is possible. Back to the drawing board…