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Here's the (mostly) finished autoharp. I still need to put some
kind of finish (oil or lacquer)
on the new chord bars, and figure out a better scheme for the chord labels.
I guess I should have taken a "before" picture, but it was a standard
"ChromAharP". I took off the logo sticker -- mostly because I couldn't
stand the random capitalization. The original chord bars were pine wrapped on the top and sides with dark-brown-painted thin sheet metal, with white plastic buttons, the same width as the bars. They followed the "standard" available chords and layout as the Oscar Schmidt 15-key autoharps, |
| The bars themselves are made out of a chunk of mahagony I had out in the garage
left over from other projects. They're about 3/8" wide (dictated by the guides in the
plastic end pieces), and I decided to make the buttons wide and tall, unlike the original
easy-to-miss-and-fall-off-of skinny buttons.
Since there are two rows of buttons, each bar can "steal" half a bar's width
from each side, making them, now that I look at it, a lot like piano keys. I "tilted" (as much as I dared) the lines of buttons to match the direction the chording hand comes in at 'em (assuming the traditional "strapped to one's chest" playing style). The choice of the chords themselves, and the locations/order they belong in is another issue, which I'll address on the next page. |
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A single chord bar. I've done some ergonomic design for notebook computers and
such, and frankly, you'd be hard pressed to design a better Carpal Tunnel Syndrome generator than
these held-upright autoharps. The left (chording) hand is bent, pretty hard, at the wrist, and
then asked to forcefully press buttons, over and over. I'm amazed there's not a class action lawsuit
going against Oscar Schmidt... Anyway, to help with that, I made the buttons pretty tall, so the wrist doesn't have to bend so far. They really ought to be 2 or 3 inches tall, but that would look pretty strange. |
| Here you can see the profile shape of the buttons. They were kind of tricky to make, but I just cut a long piece of wood and created this profile on the table saw. Then I sliced 15 buttons off. |  |
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A comparison of the old chord bars to the new ones. Same length and width, way different buttons, and there's more "wood" and less "felt". More on the felt later. |
| Here you can see the height difference. The two bars are aligned at their top surface, showing the much taller button, and the taller overall bar height (wood plus "felt"). Increasing this dimension puts the felt closer to the strings, and shortens the "throw", making it much easier to play. The bars move only about an eighth of an inch when pushed. This was a critical dimension, and took a while to get right, especially since the treble end of the bars can be closer to the strings than the bass end, meaning that the treble end is a little taller than the bass end. |  |
 
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The original ChromAharP (and Oscar Schmidt) chord bars have used 1/4" felt from
time immemorial to damp the strings. This is hard to come by, so I thought I'd look for an alternate
"modern" material. Gauging by the firmness of the original felt, I thought I'd try "Fun Foam", a 1/8"
foam material that kids use for crafts these days. A 14x22 inch sheet was 99 cents at the craft store. I made the bars out of one piece of wood, so I just glued the Fun Foam sheet to the block with wood glue, and ran it through the table saw (foam up) to slice off the bars. Worked fine. But, the foam is a little too stiff, in practice. It worked, and you can see the little circles at each end caused by the chord bar "return" springs. But it's about the same as the original felt, which frankly I think is too stiff -- it was too stiff at least for my young daughters' little hands to get clean chords. So, continuing my materials-blasphemy, I got an 8x10 sheet of white, "self-adhesive" craft felt -- $1.29. I was afraid that gluing on normal felt would end up with a stiff glue layer between the felt and the foam, but the "peel-n-stick" felt was easier, and the glue is masking-tape-like, so it's flexible. The result is really quite good -- the felt is soft to "grab" the strings (and this "craft felt" is much softer than the traditional autoharp felt), and the foam provides enough "give" to accommodate any unevenness in the string heights. I don't think that the thin felt stuck straight onto the wood would have worked. I just stuck a big piece of the felt onto the bars, and sliced them back apart with a sharp knife. |
| Since I had already marked and sliced the open string notches in the Fun Foam, it was easy to cut them in the felt -- just a little snip on either side with the pointy scissors. |   |