HUNTSVILLE, Alabama - Kate Berkholtz is about to get a new hand, but the beautiful, blond 2-year-old couldn't care less.

It's too much fun chasing her brother around The Little Gym in south Huntsville with a big foam noodle in her right hand. That's the hand with fingers, the one that came whole when Kate was born. It's not the one with just a thumb, the one left fingerless by some mystery in the womb. That hand has brought everyone here, where Kate is a student, and where The Little Gym's owner, Angel Hundley, is married to a man with a high-tech company whose slogan is, "We're helping to engineer the future."

Jessica Berkholtz, Kate's mom, sits on the gym mat and calls her daughter. Mom's next to a big guy with bangs named Shawn Betts and a small woman with a coppery red hair and wide smile named Megan Beattie. Beattie is an engineer at Zero Point Frontiers, Betts is an intern and engineering student at the University of Alabama in Huntsville, and the combined age of all three would barely qualify for Social Security.

There's a plastic tub beside them, and Betts is pulling things out and putting them on the mat. That is interesting, and Kate keeps a close eye on Betts as she comes near.

Plastic hands for Kate are what're in the tub. Betts has made several and one for him to show her how they work. There could be plastic hands for everyone in the room for not much more than the cost of dinner at the Mellow Mushroom next door. The hands cost $5 each, thanks to the new technology of 3D printing.

But cheap hands are no good if they aren't good hands. So everyone watches as Kate bends her wrist the way Shawn shows her. Will the little fingers curl? Will Kate want to wear the hand?

Technology at play

The technology at play in The Little Gym has been around a few years. It's falling in price so fast people are buying 3D printers to watch their kids make plastic jewelry and other toys. Jason Hundley bought a 3D printer last year to see how it might change systems engineering and design at Zero Point Frontiers.

Small 3D printers use a hot tool to heat plastic coming off a roll like line comes out of a weed whacker. The machines build up layers of plastic following a computer design until a real object is formed: a screw, a wrench, a hand. Larger versions use lasers and metal powder and are building everything from rocket parts to hip replacement joints.

Plastic hands are new. South African carpenter Richard Van As and special effects artist and puppeteer Ivan Owen of Bellingham, Wash., started things when they teamed up in 2012 to make aluminum fingers for Van As after he lost two fingers and damaged two more in a shop accident.

Owen had already invented puppet hands that use thin steel cable to bend the fingers, much like tendons move real fingers in a human hand. It wasn't long before the men were making an aluminum hand in response to a plea from the mother of a young boy with no fingers - just like Kate.

Owen had the idea of printing plastic hands and contacted 3D printer manufacturer Makerbot. The company sent the two men a free printer, and there was no stopping them. Now, the design software is posted online at Thingiverse, and anyone with a printer can make a plastic hand. The price has fallen from about $150 each to what each hand costs Zero Point Frontiers.

Hundley says the company did "some fun stuff" by modifying the design and speeding up the process. "After this, the cost of producing the prosthetic hand should be about $5," he says in an email. "Normally they cost $10,000- $80,000 and most companies and insurances won't cover kids because, well, they grow. This approach solves that dilemma by being scalable and low cost."

Fitting Kate, not great

Fitting Kate with her new hand isn't going great. One challenge is her age. Typically, Jessica Berkholtz says, kids get prostheses when they're infants or when they're about 4 years old. It either seems they've always had them, or they're old enough to have the motivation to climb the learning curves. The first young boy to get a Robohand, as Van As and Owen called their invention, was 5 years old.

Jessica and husband Michael Berkholtz know these things, because they've traveled the country looking for options to expand their daughter's choices. Kate is wonderful just the way she is, Jessica says, but the more choices she has in the future, the better. So, they've been to Atlanta, Baltimore and other big cities to see the experts. "Right now," Mike says, "the best option is surgery to transfer toes to her hand."

Prostheses are a possibility, he says, but there's the age thing, and the money thing. Echoing Hundley, he says that kids grow, and that means new prostheses. Kids also tend to get them for specific uses these days, because they don't want to wear them every day, just when they want to hold something special like a musical instrument. 3D printing could really help here.

Michael is watching closely as Betts puts Velcro bands around Kate's tiny arm. Then, Betts uses his model to show how bending his wrist will tighten the fishing line "tendons" and curl the fingers in a gripping motion.

Kate slowly bends her wrist, and the fingers on her new hand curl, too. She finds this mildly interesting - not nearly as interesting as the grownups - and she agreeably uses the hand to grasp a scarf. She even lets Little Gym owner and coach Angel Hundley show her how plastic fingers might one day encircle a gymnastics bar.

But not today. The Velcro bands aren't holding securely. The tendons aren't operating smoothly under Kate's tiny arm power. And Kate doesn't have the wrist control that Betts and Beattie want.

Michael Berkholtz has been thinking. "Finding a better way to attach it to her hand would help," he says. "Maybe a glove?" Maybe a fingerless glove like bicyclists wear? Attach the hand to the glove, and put the glove on Kate's hand. Do they make gloves that small? They do, someone says.

Megan Beattie is thinking, too, of switching to piano wire for the "tendons." "They used it for the wheels of the lunar rover," she says, so it has to be adaptable.

Everyone is seeing possibilities now. The next hand will be better. It will have a glove for better fit and wires for smoother action. And the hand after that will be even better. Michael Berkholtz lifts his daughter into his arms.

"Are you excited?" he's asked. "Yes," Berkholtz smiles. "This is something that could grow with her."

"Will you keep going?" Jason Hundley is asked. "Absolutely," Hundle says. He gestures at the gym mat. "The unit cost is $5," he says.

Kate is done. She's ready to go swimming now, and that starts a new discussion. Maybe they could print a paddle to attach to the glove. Maybe they could print a hand that could hold a fishing pole.

By now, everyone knows what's on the floor isn't just a new hand. Scattered on the gym mat is the new world Kate gets to live in.

Updated on Aug. 20 to add additional comments from Jessica Berkholtz