Tucked into an ordinary-looking building just outside the sleepy center of West Grove, there's a high-stakes process underway.

Josie Gluck and Michael Schunke are making goblets, which are just about the most difficult project glass artists can undertake. Each one is made of very thin, delicate parts, and the glassmaker only gets one shot to put them together perfectly - or ruin the entire thing.

"That's one of the things I like about glassmaking," Schunke says. "There are a lot of now-or-never moments."

Their willingness to embrace those is what sets apart Vetro Vero, their line of ruthlessly precise and elegantly wrought functional artworks in the form of jewel-colored, two-toned vases, crystal decanters adorned with gold leaf, and their trademark, intricate goblets.

From their unlikely design hub in Chester County, Schunke, 45, and Gluck, 36, regularly ship to high-fashion retailers such as Barney's and Bergdorf Goodman, and land placements in design publications such as Vogue, Elle Décor and Dwell.

They're also showing at the Philadelphia Museum of Art Contemporary Craft Show, which runs through Sunday at the Pennsylvania Convention Center.

Despite the company's acclaim, it remains a two-person business, located in a 19th-century creamery building that Schunke transformed into a glass studio, next to the house they share. Schunke and Gluck said that will never change: After all, their partnership is a perfect harmony - and its seamlessness is reflected in the precision of their work.

Schunke had his own glass studio when they met in 2008. He was teaching a class at the Haystack Mountain School of Crafts in Maine, and Gluck was his teaching assistant.

Gluck, who had worked in the studios of Dale Chihuly and Lino Tagliapietra, was his teaching assistant again at another class at another craft school. That's when the two began collaborating in the studio.

"We just kind of fell into step," she said.

Now, they fall into step on a daily basis in their studio, where their glassmaking practice is a pas de deux that moves fluidly between various furnaces and the work bench where the glass is blown, molded, trimmed, and adjusted as it cools.

Making each piece is a two-person job that can take 12 minutes or all day, depending on the complexity of the project.

On a recent morning, Gluck began gathering a bit of molten glass from a heated crucible, the first step in making stemless wine glasses, each with a ball coated in gold leaf embedded in the base. There was no discussion as she brought more molten glass over to Schunke, who was counting on her to bring it over at just the right temperature, and blow just the right amount of air into a long pipe to transform it into a clear balloon, while he shaped it into a goblet.

"We're not really interested in the organic nature of the material or letting the glass decide what it wants to be," Gluck said. "A lot of the time you hear that from artists, that they're interested in embracing the moment. We're more interested in controlling the outcome."

That outcome has attracted commissions from collectors, and from the gift shops of museums including the Barnes Foundation and the Museum of Art and Design in New York. Their pieces sell for $150 to $1,800; goblets are about $300 each.

The work also has drawn interest from glass-art centers around the world. They regularly invite the couple to teach their glassmaking techniques, and to talk about their design practice, which alternates between hand-sketching (which is his preference) and computer-based design (which is hers). Schunke is red-green color-blind, but selecting colors is also a collaborative process.

Next year, they'll lead classes at the Pilchuk Glass School in Washington State.

"They have such a fine-tuned sense of design," said education coordinator Becca Arday, who invited them to Pilchuk. "They're combining different techniques in the glass world in unique ways. They're definitely influenced by historical design work such as what you'd find at the Venini factory in Murano. But they're combining Italian, Swedish, and what looks to me like Japanese aesthetics. Their forms are timeless."

They're also role models for a growing number of young people looking to launch careers in glass making.

"I can think of maybe a handful of artists that are doing successful business in the high-end craft world," Arday said. That's partly because the overhead for a glass studio is high, and partly because it's just a lot of work. "People do it because it's what they love. It's definitely a passion."