Richard Van As was working in his home near Johannesburg, South Africa, in May of 2011, when he lost control of his table saw.
"It's a possibility that it was a lack of concentration," he says. "It's just that the inevitable happened."
The carpenter lost two fingers and mangled two more on his right hand. While still in the hospital, he was determined to find a way to get back to work. Eventually, solving his own problem led him to work with a stranger on the other side of the world to create a mechanical hand using a 3-D printer. Other prosthetics, including a lower jaw, have been made with the technology before, but making a hand is particularly tricky.
As soon as he got out of the hospital, Van As began researching prosthetics online. They cost thousands of dollars money he didn't have.
So in the meantime, he rigged up an artificial index finger for his right hand with materials from his shop. But he kept looking for help or a collaborator someone who could help him fix his hand.
In time, Van As came across a YouTube video from Ivan Owen. In the video, Owen, a special effects artist and puppeteer in Bellingham, Wash., was demonstrating one of his creations, a big puppet hand that relies on thin steel cables to act like tendons, allowing the metal digits to bend.
"The complexity of the human hand has always fascinated me [and] really captured my imagination," Owen says.
The two began working together long distance Skyping, sharing ideas, even sending parts back and forth. Finally, Owen flew to South Africa to finish the work in person with Van As. And today, Van As has a working mechanical finger to assist him with his work.
But something else happened on Owen's visit to South Africa: While he was there, Van As received a call from a woman seeking help for her 5-year-old son, Liam Dippenaar, who was born without fingers on his right hand. The cause was a rare congenital condition called amniotic band syndrome. In ABS, fibrous bands can wrap around a hand or a foot in utero and cut off circulation.
Van As says he and Owen looked at each other and were of one mind: " 'Yeah, easy, no problem.' "
Within days, they developed a crude, mechanical hand for Liam, with five aluminum fingers that opened and closed with the up and down movement of Liam's wrist. Owen still remembers the 5-year-old's reaction when they rigged up the device for the first time.
"He bent his wrist and made the fingers curl," Owen says. "You could see the light bulbs go off and he looked up and said, 'It copies me.' It was really an incredible moment."
When Owen flew back to the United States, he wondered if the device could be turned into printable parts.
So he emailed MakerBot, a firm that makes 3-D printing equipment, to see if the company would help out. It did, offering both Owen and Van As a free 3-D printer. "Then there was no stopping us," Van As says.
What had previously taken the pair a week's time or more milling finger pieces, adjusting and tweaking parts now took 20 minutes to redesign, print and test.
Eventually, Liam's crude hand was replaced with the improved 3-D-printed version, which Van As and Owen call "Robohand."
"After practicing with it for a little while, Liam was able to pick up a coin, grab objects of different shapes and sizes," Owen says. "He's a really determined little guy."
They posted the design and instructions for Robohand on Thingiverse, a website for sharing digital designs. Anyone can download the plans and with a 3-D printer and about $150 in parts make a hand.
Videographer Paul McCarthy and his 12-year-old son, Leon, live in Marblehead, Mass. They discovered Robohand on the Web and decided to make one for Leon, who was born with no fingers on his left hand. Printing the parts (using a friend's borrowed 3-D printer) was easy, the two say. But it took them a month to figure out how to string, screw and bolt together what they describe as the "Frankenstein" version. It's still a work in progress, they say, but several weeks ago, Leon wore it to school for a tryout.
"I'm able to hold a pencil and piece of paper," Leon says. "I've done a lot more than I ever thought I could, so it's opened up a lot of new doors in my life."
Paul McCarthy says there were few options for his son. The doctor's advice when Leon was very young was to get used to using his hand without prosthetics and try to acquire a full range of abilities and motion. Leon should first learn to navigate the world relying on his one fully functioning hand and the partial dexterity of his other hand, the doctor advised.
"So the last time we went to visit his hand doctor, he recommended maybe we could start looking for prosthetics," Paul McCarthy says.
And that's when father and son found the YouTube videos of little Liam in South Africa.
So far, in addition to his work as a carpenter, Van As has fitted more than 100 children with Robohands. He doesn't charge anything not even for the parts but he does want to train others to learn how to assemble the devices and properly fit kids with them.
To do that, he's raised some money, and with more people helping, more people will get hands, he says.
Like Leon McCarthy.
"Leon came bouncing out of school with this biggest smile," Paul McCarthy remembers. He remembers Leon saying: "Look, it's working, the Frankenstein hand is functioning! I am holding my lunch bag."
But getting the fit just right was hard for McCarthy and his son, and experts in prosthetics say users are bound to have these kind of challenges.
Matthew Garibaldi, director of orthotics and prosthetics in the Department of Orthopaedic Surgery at the University of California, San Francisco, says that making sure a prosthetic device fits is essential for it to work well.
And there are limited options for pediatric prosthetics, Garibaldi says, because there aren't many kids with upper-extremity amputations. That's one reason a device like Robohand is so appealing, he says. "Its primary function is to decrease manufacturing costs and increase productivity."
"The timeliness of this technology couldn't be better," Garibaldi says.
And the world of 3-D printing is moving quickly. A new version of Robohand is now available it's designed to snap together like Legos. Materials for this version will cost just $5.