Teacher 3D prints working prosthetic hand for student in school lab

Scott Johnson noticed something early on: Jackson Farmer, a kindergartener born without a right hand, would crack jokes about it. One morning, Farmer offered Johnson his rubber prosthetic with a grin — "Hey, do you need an extra hand?" Johnson, a STEAM educator at Red Cross Elementary in Glasgow, Kentucky, got hooked. Not by the joke, but by the question it raised: what if this kid had something that actually worked?

For years, Johnson watched Farmer move through school wearing a silicone hand that looked real but did nothing. It was cosmetic. Then Johnson had an idea. His lab already had 3D printers. His curriculum already taught students to design and build. Why not make something functional for Jackson — something he could actually use to write, to play, to do the things fourth graders do.

From idea to 25-hour print

What followed was a year of trial and error. Johnson tapped into E-Nable, an online community of volunteers who design and share free or low-cost prosthetic files. He consulted with an engineer in Denmark to refine the design. The challenge wasn't the printing — it was making something lightweight enough that a child would actually want to wear it, something that moved naturally without batteries or motors.

The breakthrough came with simplicity. Johnson used fishing line threaded through the fingers, connected to a fulcrum lever at the wrist. When Farmer flexes his wrist down, the fingers close. When he relaxes, they open. The whole thing is printed from corn plastic — a biomaterial — with rubber fingertips and foam padding inside. Twenty-five hours of printing. Between $20 and $30 in materials.

When Farmer first put it on, he said it felt right. His favorite thing: trying to write with it. "I'm not that good, but I try," he told reporters. But what struck him most was the independence. "It just makes me feel like, 'yay, I get to do stuff on my own.'"

The hand that grows with him

Here's the part that matters most: if the hand breaks, Farmer doesn't need to wait for a specialist appointment or a new prescription. He walks to the school lab and prints a new part. He's already gone through three palms from rough play at recess. And when Johnson needed to reprint a thumb, Farmer helped. Johnson's plan is to hand over the digital files to Farmer so that as he grows, he can print his own replacements — no adult needed.

This isn't a heartwarming one-off. Johnson's approach reflects something deeper about what he believes a school lab should be: a place where every student, regardless of ability, can create and solve real problems. His work earned him Kentucky Teacher of the Year in 2025. "All of my students, all of their backgrounds and their different ability levels, can create in our space," he said. "We don't treat our content as a subject or a means to a grade, but rather as information for life."

For Jackson Farmer, the prosthetic hand is just the beginning — a tool he helped design, can repair himself, and will carry forward into whatever comes next.