It will outline some problems with the first iteration, fixes to those problems and problems that those fixes created.
I'll be referencing the Chime SF project frequently and will send you off to the relevant steps in that Instructable.
While most of the changes made are cosmetic, some crucial features have been added to upgrade the stability, durability, playability and access for maintenance of Chime.
Step 1: Sounds the Same, Smells Different Though...
After playing with a lot of ides about how to make this a new thing, it became apparent that Chime already had a voice and was already well suited in functionality and musicality, to Market Street. For that reason the decision to focus on tightening everything up instead of expanding the system.
I'm going to send you to the first Instructable for a description of the sound source and my work to get there. During this year's festival Market Street proved to keep a pretty consistent tuning. The pedestrian traffic patterns and interactions were also consistent.
Chime is a gathering place and creates very definite pauses. As passersby stop to engage with the structure they make its function evident in an impromptu performance. The new features and makeover only added to the enticing form and sounds.
A consistent comment throughout the weekend long festival was "it smells great!" This time instead of pine lumber from the big orange hardware store, Alaskan Yellow Cedar was used. It is light in color and a great choice for outdoor woodworking projects. It also smells even better than pine. Almost everything wooden was made from 1x4"s screwed together as last time. A lot more precision and care was taken to ensure precise replication of each of the 7 sections that make up Chime's body though. One of the major problems last time was the hammers' tendency to rock out of place over time. this would in turn lead to missing contact with the chimes and hitting the lever panels directly behind them and damaging them.
Step 2: Suspending Chimes
A couple of internal changes were made that significantly improved durability and stability of Chime. The first I'll delve into was the decision to mount the chimes on a rod attached to the frame instead of hanging them from cords or cables. I resisted this option for a long time because I didn't want to impede their sustain but eventually settled on a latex rubber sheath for a 1/4" rod to hold things in place. (I'd recommend increasing this rod to at least 5/16") The rubber tubing used to cushion the chimes fit the rod perfectly and gave plenty of freedom to ring clearly with no loss in sustain.
I was really dreading drilling the metal tubes again. It has been challenging to get these holes done in the past. This time I made a layout template so I could align the holes precisely across from one another on the diameter. This was done by fabricating a simple rectangular trough with walls the height of the radius of the tubing. Its width was exactly that of the diameter so that the tube fit snuggly into it. Then I could easily draw a line down both sides and make the center punch marks at the exact right place. Super simple and really effective. The other thing that helped the process was drilling bigger hole (17/32" instead of 1/4") to accept the newly cushioned rod. The larger diameter drill bits don't tend to flex like the skinny ones, ensuring precise placement of the hole. The actual drilling of the hole still required a "V" grooved holder for the drill press.
Here's the link to the last instructable with more details about all those HOLES.
Step 3: Alignment of Moving Parts
Last time around there was a lot of slop built into the mechanics of Chime. It ensured that things worked fairly regularly but required more maintenance than was sustainable as a longer term installation. However simple the instrument is, every action creates wear on the system. The duration between maintenance had to increase so this time around the task was to tighten everything up for durability and consistency.
The mechanics are still the same in the new version of Chime but with less wobble. To achieve stability and consistent alignment of the moving parts spacers were used to keep the brackets that attached to the pivot points of the push and pull pendulum mechanism in their places. Nylon tubes can easily fit around the rods used at these pivot points.
A double armed hammer was used in conjunction with these spacers to further stabilize the hammer. Instead of the original single armed hammer whose pole ran through the mallet head, two bars were used to capture the mallet head on both sides. Having two points of connection to the main axle paired with spacers to hold them in place virtually eliminated any misalignment in the moving parts.
My personal favorite thing that the new hammer style did was to provide a swing for my phone so this view is possible.
Step 4: Interface Design
For a longer term installation a major concern was the certainty of damage to Chime's exterior. It could be simple scuffs, graffiti, carving, moisture damage, to outright breakage or even fire. To mitigate the eventual repair work that will have to be done, the lever panels for this version were fabricated using horizontal slats that could be replaced individually instead of a large labor intensive curved board that will have to be remade or just accepted as its condition changes. A simple fix that presented another challenge in alignment of all of these 252 slats across all 14 panels. Nothing that a half inch spacer couldn't handle though.
The lever panels also ended up being a solution to the ADA access requirement for a cane detection rail. Everything else had been well considered and accounted for except sight impaired individual's access and the need for some kind of cane rail warning. The even curve that was initially proposed for this structure had its widest point at the center, approximately 36" above the sidewalk. This put sight impaired individuals at risk of missing an early warning with their cane and potential harm when the lever panels are in motion. I'll spare you the Details but highly recommend looking at them for this and all other access guidelines for any public works you might have in mind. The fix for Chime was to drop the widest point of the bulge of the lever panel to 27" and to make sure that the upper portion didn't protrude beyond that bulge at its farthest extension.
It was a very interesting process to get to that solution. Weeks were spent sketching, discussing and creative shopping for external fixes to no avail. The solution was already built into the structure of Chime though. It took a lot of perseverance, an open mind and many different perspectives to find the most elegant way there though.
Step 5: Assemble
So you might have enough information between this Instructable and the ChimeSF instructable to build the new version...
In that case, the next logical step would be to assemble the sections into a complete structure, or Chime Voltron. If not, oops. You can always get in touch with us at civicharmony.org for a consultation.
Each section of chime relies on the others for stability in use. That's just one of the beautiful things about a modular design. Put 'em together and you get a better thing.
Spend the time to lay everything out and replicate each section fastidiously and the final assembly should be a cinch. It's really just sticking them next to each other in the right order, drilling a 1/2" hole in the 4 corners of each touching face and bolt the things together. 2 1/2" carriage bolts and lock nuts worked out pretty well. I don't think there is really a way to secure the connections against tampering that would allow for ease of access if a large repair had to be made. But if you decide to build this or something like it and you want it to stay in one place forever then get longer bolts, tighten the sections together and take some vise-grips to the threads of the bolt and mangle them so you'll never ever get them apart without cutting them apart.
Step 6: End Panels
One of the most striking aesthetic differences in this version of Chime are the panels that cap both ends of the structure. The trapezoidal slatted walls serve as physical barriers to access of the inner workings of Chime while still leaving slim openings to peek inside at the mechanics of the whole thing.
They match the shape of the sections and bolt on separately. This reduces the weight of the outer sections and gives an access point should internal repairs be required. For the next build The panels will be hinged and padlocked so even easier access can be had.
Step 7: Roof
This roof was in the same style as the last one.
It's cleaner though. I really enjoyed using a circular saw with an abrasive wheel to cut the tin panels. Very pretty and much faster and much more accurate than the tin snips from last time.
To give the whole thing a more finished look the eaves of the roof were trimmed with a wooden fascia all the way around. This also protected users from potential harm from sharp edges of the roofing tin.
It's pretty fancy if I do say so myself.
Step 8: Notes
Chime is an evolving project. It's been harrowing and rewarding. The biggest payoff for me is to just let people play it. It's a simple thing to understand and interact with. It's also simple enough to ignore if you're not into that kind of thing. I love the way people gather in clusters and dissipate over time. And I love being surprised by silence when everyone decides they're done playing it.
Also, that picture, that's Bart Hopkin. He's the guy whose bar calculator I send you to for tuning chimes. He's also the guy who literally wrote the book on experimental musical instruments and a major inspiration for this project and any other instrument building i do. I'd like to take a second to say thanks to him for sparking the recognition that I could make musical instruments that don't have to adhere to anything but physics and my own imagination. So... thanks, Bart
I know this instructable is light on real details of the build but it's really not that hard. Mechanically it's pretty dang simple. I highly encourage you to give your own spin to this type of project. If you want to do something good for your neighborhood, find a way to make some music together.
Hit me up for details if you want them.
Otherwise check in at dangottwald.com or civicharmony.org for updates on upcoming events and projects.