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A Helping Hand


Leon McCarthy, 12, was born without fingers on his left hand. He could do many simple tasks. But he could not grasp more than one thing at a time. So Leon's father, Paul, created a prosthesis, using a 3D printer. Now Leon has fingers that open and close with a flex of his wrist. "It was a do-it-yourself adventure," Paul McCarthy told TFK.

With his artificial hand, Leon McCarthy can accomplish many tasks, including slicing fruit.


When Leon was a baby, his parents were told not to get him a prosthesis until he was in his early teens. "The doctor said Leon should first learn to get full use out of the hand he was born with," says McCarthy.

As Leon got older, his father looked into buying a prosthetic hand. It can cost as much as $30,000. So McCarthy came up with a less expensive solution.

Finding Robohand

The McCarthy family lives in Marblehead, Massachusetts. McCarthy found a video about Robohand on the Internet. It is a prosthesis built with a 3D printer. He downloaded the free instructions. All he needed was the 3D printer—which costs $2,000—and some materials.

Leon McCarthy, 12, was born without fingers on his left hand.


Luckily, Leon's school had just acquired a 3D printer. Science teacher Bill Sullivan offered to help McCarthy build the hand. The materials were not expensive. "They cost about $10," says McCarthy.

With his new hand, Leon can do things better. "I can help my mom more," he says.

But there's one thing Leon still wants to accomplish. "The goal," he says, "is to be able to tie my shoelaces."