2026-03-28

Last modified: 2026-03-28 15:12:11

Keyboard Glockenspiel

Here's a schematic for the damper:

I know not very easy to read.

Basically the pivot would be in the front half of the key, and the base would rest on the bottom at the very back of the key, and the damper would touch the tone bar near its middle.

We get:

• 1.8mm horizontal rubbing on the bottom of the cae
• 3.8mm vertical drop of the damper
• and most importantly, very little intersection with the hammer path

The main downside of this layout is that the damper mechanism is really big, which means flexible and potentially takes ages to print. But if it works well I can probably live with that.

The only remaining intersection with the hammer path that isn't trivial to avoid is the link between the pivot and the bit that rubs on the base. If I redesign the hammer path so that at the rest position it has more clearance from the bottom of the case then I can probably avoid that.

We still need a way to adjust the exact position of the damper. Potentially you would do that by adjusting the position of the tone bar? The hammer action is much less sensitive to the exact height at which it contacts the tone bar than the damper is, so I think this would be acceptable. Failing that, integrate a flexure in the damper lever which can be opened/closed with a screw to move the damper pad slightly.

Here's a version with no intersections:

Hammer lever ratio is reduced from 6x to 5x but may still be fine.

Here's a pretty rough animation of the action:

(It's rough because I created it by manually rotating/translating the parts).

And we can see that I have made some sort of error, because the hammer rises much too far. It's meant to stop short of the tone bar with the key bottomed out, to be carried the rest of the way by inertia.

But actually maybe this is a good thing, because it means the lever ratio was larger than I thought, maybe it is more like the 6x I originally wanted. Just need to move the tone bar higher and make the damper taller.

Oh! One other oversight... I was intending to use a vertical pin in the centre of the pivot to keep the pivot in the right place, but that will interfere with the damper lever. I think I can make a hole in the damper lever to clear the pin and the rest is fine.

Oops, I forgot that there was provision for a 2mm tall felt damper at the front of the key, so it wouldn't actually tip that far. It still overshoots the tone bar, but not as badly.