A Handy Tool

Leon McCarthy, 12, talks about the prosthetic hand his father built for him using a 3D printer.

Jan 10, 2014 | By Glenn Greenberg
TAMMY VIPPERMAN

It is easy to make a new hand for Leon as he outgrows one, or if it becomes damaged.

TFK:

What did you think when your dad first suggested building a hand for you with a 3D printer?

LEON McCARTHY:

It seemed like it would be very hard to achieve. But it wasn’t. It was actually a lot of fun to make.

TFK:

How often do you wear the hand?

LEON:

I don’t wear it all the time. I use it like a tool. I only use it when I need it.

TFK:

What does the hand allow you to do that you couldn’t do before?

LEON:

It really helps me do things better. I can carry more than one thing now. I’m able to hold two grocery bags and help my mom carry them. Without the hand, I can rest a grocery bag on my left arm, but because that arm is shorter than the other one, there’s not a lot of room for the bag to rest on.

TFK:

How does the hand work?

LEON:

The fingers close when I bend my wrist, and they open up when I release my wrist.

TFK:

How does it feel when you’re wearing it?

LEON:

It’s pretty comfortable. But there are still some edges that we need to smooth out because they dig into my skin.

TFK:

What was the reaction of the kids at your school when they saw the hand?

LEON:

They wouldn’t leave me alone! They all wanted to touch it and they asked me a lot of questions about it.

TFK:

What are some changes you’d like to make to the design?

LEON:

It’s made of plastic, so it’s kind of slippery. I can’t get much of a grip. So I’d like to add some rubber to make it easier to grasp things. I’d also like the fingers to close completely. They can’t do that right now, so I’m not able to hold thin objects like a pencil. And I’d like to add a laser pointer.