WORCESTER — On the top floor of an old industrial building at 41 Jackson St., steps from a factory where garment workers a hundred years ago made women’s corsets, a printers’ cooperative is stoking a political revolution, one T-shirt and one coffee mug at a time.

WorX Printing, a worker-owned union print shop, turns out materials every day for the online shops of two of the Democratic Party’s leading lights, U.S. Rep. Alexandria Ocasio-Cortez, D-N.Y., and U.S. Sen. Elizabeth Warren, D-Mass., among a host of other progressive political organizations and causes.

Clients have included the Women’s March, Democrats.com, the American Friends Service Committee, Oxfam, the Green Party, Act Up, and chapters of the Democratic Socialists of America in Worcester and elsewhere.

“DSA chapters are finding us in droves right now,” said worker-owner Kevin O’Brien. “We’ve probably worked for a dozen now. They’re specifically looking for worker-owned union shops.”

They’ve also done jobs for Joe Biden’s political action committee, American Possibilities — hence the “Cup of Joe” mugs that could be seen in the print shop Wednesday.

Mr. O’Brien was asked: Is Biden getting into the presidential race? “Can’t say,” he replied. “Joe has really kept things close. I think we’re all hoping he runs.” And if Biden does, and comes here to have his shirts done? “That would be fantastic,” Mr. O’Brien said.

Alas, he acknowledged Thursday, a competitor in Texas had scored the Beto O’Rourke campaign printables account. But the Kirsten Gillibrand online store, about to launch, will feature shirts and other materials from WorX, he said.

Mr. O’Brien said the Worcester shop works with a partner, FII Marketing, in Cranston, Rhode Island, which has been involved in Democratic presidential campaigns since the Carter administration, and has attracted a large national clientele of progressive political and allied organizations.

“What we do here is pretty unique,” Mr. O’Brien said. Most people might think of a print shop as a large-volume place that takes one design and prints a lot of it, he said. “We do the exact opposite,” he said. “We print one at a time, after it’s ordered.”

On the shelves of the workshop Wednesday afternoon were examples of the items they’ve been turning out: coffee mugs with Elizabeth Warren and Alexandria Ocasio-Cortez slogans, and samples of the newly iconic AOC campaign posters.

Taped to a girder was a long list of Warren orders to be made and shipped that day, bearing various slogans: “Win With Warren,” “Dream Big, Fight Hard,” “Nevertheless She Persisted,” “The Best President Money Can’t Buy,” “Impolite Arrogant Women Make History.”

When Ms. Warren announced her presidential campaign in February the shop experienced a flood of orders. “You take in the orders and you chew them one bite at a time,” Mr. O’Brien said. “She’s an amazing candidate. People really love her message.”

A flurry of activity was sparked in October when an email by White House chief of staff John Kelly surfaced in which Ms. Warren, a progressive favorite, was described as an “impolite” and “arrogant” woman. “That night we scrambled with the (Warren) campaign to print 'Arrogant Woman' T-shirts,” he said. “By the end of the weekend, we had enough work to do for a long time.”

The largest printing run they’ve done? “We’ve certainly done thousands,” he said.

Mr. O’Brien, of Auburn, who turns 48 this week, was raised in Holden, son of a longtime Norton Co. employee who was laid off after 30 years of service. “I promised my dad, before his passing, that I would seek out alternate forms of ownership for myself and for Worcester," he said.

He said the worX Printing Cooperative, part of the Cooperation Worcester movement and the United Steel Workers Local 2936, was launched in 2014, and had its first big year in 2016, when it printed materials for Hillary Clinton.

Worker-owners with Mr. O’Brien are David Grybowski and Tony Piscopo. The shop has two part-time employees, Sheri Grant and Erik Orellana, and during spikes in business hires extra help at $15 an hour, Mr. O’Brien said.

The startup operates out of space in the Clark Mailing Building on Jackson Street provided by Clark Mailing Service, a third-generation family business that does direct mail for Worcester colleges and businesses. “Our work would not have been possible without the Clark family’s generosity during our incubation stage here in their facility,” Mr. O’Brien said.

Mr. O’Brien sees big things ahead for the worker-owned print shop as the 2020 presidential campaign looms and a growing number of Democrats enter the field, all boosted on websites with online stores offering merchandise that supports their candidacies.

“We have a huge opportunity for growth here,” Mr. O’Brien said. “What we’ve been told is, how much volume can you handle? There’s 10 times the volume sitting out there now waiting for us. We’re really all hands on deck trying to figure out how to build out our capacity.”

He said he hopes eventually to work with more local candidates.

“Anybody who is thinking progressively about how to keep jobs here in the United States I’m open to doing business with,” he said. “That’s what we’re here to do - to build more jobs.”