finn’s bow

Finn Thompson (center) watches intently as Sigmond Kukla (left), a fourth-grader at Washington Elementary, makes an adjustment to the “bow holder” wrist brace as fifth-grader Kate Mooney, looks on. Kukla and Mooney designed the 3D printed brace to help Finn grip the bow , enabling him to play the cello with more ease. Finn began playing the stringed instrument in September.

What happens when a librarian is inspired, kids are curious and a little boy captures the hearts of a community? Innovation.

Parallel situations were happening within Washington Elementary School. The music teacher, Diane Sadar, had a new third-grade cello student, Finn Maxwell, with a great ear and even greater dedication, but a pesky challenge with his right hand. His mild cerebral palsy did little to slow him down in life, but when it came to holding his cello bow it was a menace. She spent the fall of 2016 looking for ways to help him get a grip on the bow.

Over in the library, a handful of kids were embracing the possibilities of a new 3-D printer courtesy of a grant from Intermec Foundation based in Seattle, Washington. Their leader, librarian Rae Ann Macosko had gone through training to apply the printer’s use to STEAM (Science, Technology, Engineering, Arts and Math) programming. The printer was a complex and temperamental tool that she and the kids embraced but wished they could use for a real-world purpose. Then, the worlds of art and science harmonized.

Instrumental Inventiveness

Cello bows are delicate things prone to imbalance themselves. Musicians must be aware if the strings become too frayed on one side and also need to avoid too much “skin chemistry” or extreme temperatures to name a few potential hazards. Navigating the right grip is difficult for any beginner.

Sigmond Kukla (left), helps attach the “bow holder” to schoolmate Finn Thompson’s wrist, as fifth-grader Kate Mooney, looks on. Kukla and Mooney designed the 3D printed brace to help Finn grip the bow , enabling him to play the cello with more ease. Finn began playing the stringed instrument in September.

Modifications are common for kids who play instruments. Sometimes their hands are too small, or they just can’t get the hold right. But usually tweaks that facilitate the stroke of the strings involve primitive materials like rubber bands.

In a moment of providence, the music teacher attended an in-service session taught by the librarian. As Sadar sat listening to an overview of the new technology coming to Washington, she wondered. Was there a solution to be invented here? After some quick research, the two women found some digital designs at for things that could be made on the school’s Makerbot 3-D printer to  help solve Finn’s challenge.

Two students who had been working with Macosko immediately embraced the idea of a gadget for Finn’s bow. Quite literally, necessity was the mother of invention. Fifth-grader Kate Mooney and fourth–grader Sigmond Kukla saw that a 3-D printer could do what any makeshift rig could not. The printer could bring their imagination to life.

Imagination and Tech Savvy

“We were using the printer to make things like a mini colonial day dress model and soccer shin guards,” says Kate. That stuff was cool, sure, but she always was seeking to design things that might solve a problem. Sig was an old pro at 3-D printing, having regularly entered competitions to win a printer of his own, which he eventually did.

The grip support enables Finn, a funny, happy kid who has a mild disability, loosen his hold on the bow and relax, creating a therapeutic effect for his arm. He’s looking forward to working with the 3-D printer himself in the future.

Through the process of tackling the technology of his own 3-D printer, Sig had moved from designing a dodecagon-shaped pencil holder (12 angles and 12 sides) to a device to help someone with an injured hand hold a bar of soap. You might say a budding occupational therapist-engineer was born. Kate, an avid technologist who looks forward to enrolling in the Girls Who Code club at the high school as soon as she can, loved the idea of making something to help someone else.

There’s irony in Finn benefitting from a specially designed thing for dexterity. “When he was younger, we tried to get him OT support, but he started stringing the beads they gave him with his mouth and left hand. He passed the tests!” says his mother Marie Maxwell. She and her husband, Peter Thompson, know about tests. The Barth Avenue couple has adopted seven of their nine children from places near and far. Though some of the kids do face physical and developmental challenges, the whole gang is unflappable. 

Finn demonstrates how the “bow holder” stays attached to his wrist so there isn’t a need to firmly grip the bow and won’t slip from his hand. Fifth-grader Kate Mooney (right) helped design the 3D printed brace for Finn.

Everyone involved in Finn’s bow project was equally level-headed. They failed several times to produce a workable model; the 3-D printer can be arduous and snarky. Much of it was learning as they went, tinkering with designs and learning from wrong results. “They call it tinkering when you work through a variation on a thing someone has made with technology,” explains Sig. Because it was a “wait and see” project, they didn’t want to loop Finn in until they were ready. But it was too intriguing to keep secret.

The Big Reveal

Word of Finn’s bow project got out, and other kids wanted to see what it was all about. In March, Sig’s teacher Kimberly Robbins projected the hours-long printing process of the final iterations of the device live on a screen in her classroom. The big moment, of course, was sharing their invention with Finn. In a small, close-knit school it’s hard to keep a secret. Couple that with Finn’s reputation as a funny, happy kid who could give the mayor a run for his money, and it’s nearly impossible.

Kate says, “Everyone knows Finn. Everyone loves him.” Ultimately, it was his sister Maise, 9, also in third grade, who spilled the beans one night at home. His mother didn’t even know. “I set the timer every night, and he goes upstairs and practices. I didn’t realize all of this was going on about the bow,” says Marie.

“The contests make you think through an idea, and get inspired by challenges”

-Sigmond Kukla

The group had tinkered enough with the design, with Kate and Sig navigating online tutorials and quality control to supplement their learning. Now they needed to measure Finn’s arm and hand to customize it for him. It was time to fill him in.

Finn just couldn’t figure it. When he next had library, Mrs. Macosko showed him their project, in disparate parts at that moment. He tells the story: “I thought, ‘How the heck can that hold my bow?’ but then I saw the second part printing and I started imagining the parts fitting all together.”

From the vantage point of a carefree little boy, Finn had some practical concerns that he was happy this would solve. “When I was born, my left side was normal and my right side was a little bit smaller, so when I was a baby it was different. That’s why I wear a brace on my foot,” he explains. He says he liked the cello, but his hand would get tired and sweaty trying to hold his bow.

The Final Product

With some help from much more sophisticated equipment in Mt. Lebanon High School’s CAD (computer aided design) lab and some additional design and fabrication instruction from Duane Lewis and Larry Johnson in the high school’s practical arts department, the kids could fast-forward some of the final modifications and then make the most important part of all for Finn. “They actually asked me what color I would like it to be and I couldn’t believe it! So, I said orange. I love orange,” says Finn. Inspired, he’s hoping to get his hands on the 3-D printer someday. “I would print something that I would have never thought that could come in handy like a little ketchup holder as small as my thumb,” he says.

Washington Elementary library media specialist Rae Ann Macosko works with students Sig Kukla (left) and Kate Mooney at the school’s 3D printing area inside the library. The two students visit Macosko regularly to work on print ideas and utilize the Makerbot 3D printer (foreground) which the students have named “Martin.”

Fourth grade teacher Kimberly Robbins was delighted at the whole chain of events. “We struggle to find real-world STEAM connections, so to put to purpose this cool tool to solve a problem for another child was incredible,” says Robbins. “We want them to take care of each other, and here they truly did,” she says. She says the kids were so focused on their task, they didn’t realize the magnitude of what they did until they saw the tears in her eyes.

Diane Sadar says the grip support has really motivated Finn. Her too. “I’ve been thinking about other little gadgets the kids could make to help other kids,” she says.

The device enables Finn to abandon his former baseball-bat-like hold and relax a little, creating a therapeutic effect for his arm. 

As Finn gets used to his new grip, he already has plans for the future. “I will share this with someone else when my arm grows, if they like orange,” he says. “If not, I will ask that new person what their favorite color is, and I will basically do what these kids did for me.”


An integrated approach to learning that incorporates Science, Technology Engineering and Design, Arts and Mathematics.

3-D printer:

A machine allowing the creation of a physical object from a three-dimensional digital model, typically by laying down many thin layers of a material in succession.

Photography by John Schisler