By the time a U.S. flag made at Goodwill of South Florida’s Flag Center reaches Jorge Proenza, it must be perfect to pass muster.

Every stripe, “Old Glory Red” and white, must be 4.5 inches wide. Each of the 50 embroidered stars, exactly 3.3 inches in diameter, on the “Old Glory Blue” canton. And the fabric, when placed on a table, must lie flat — no pleats, no pulls, not a single loose thread.

Running his hands across the sprawling fabric, Proenza feels for imprecisions. His fingers caress the straightness of the seams, the equalness of the 13 stripes and the weave of the 100 percent American-made, two-ply cotton bunting. If the measurements of a single stripe are off by more than 2 percent, it is repaired. If one of the stars is off, the entire star field must be replaced.

But if flaw-free, he deems the 5 foot-by-9 1/2-foot standard ready to use as a burial flag, to be draped as a pall on a casket during a military funeral.

“I’ve been making these flags for over 10 years now, and I’ve always been proud of the work,” says Proenza, who is blind.

Proenza is one of about 60 employees at the Goodwill operation in Allapattah that produces about 85,000 interment flags annually for the U.S. Department of Veterans Affairs.

The prevailing sound in the cavernous flag workroom is the constant hum of sewing machines, perforated by friendly conversations or instructions from supervisors. The workers, for the most part, are silent as they focus on inspecting each star. If even a single speck of white fabric, for example, appears in the blue background, the star field is put aside.

Flags are made in two rooms. In the first, the process begins with the star fields — the 50 stars on the canton, the inner corner — that are stitched by 32-ton embroidery machines stretching across the production floor. Most of these massive steel contraptions were made in the early 1920s by Schiffli, a well-known maker of lace and embroidery machines in Germany. Goodwill got them in 2003 with its acquisition of Penn Made, a company that specialized in the production of the star fields for over 75 years.

“As long as they continue to work, we’ll continue using them,” says Ariel Alfonzo, who is responsible for managing the over-90- year-old machines.

Workers then take the machine-sewn star fields and sew the outer borders of each star by hand, trimming excess fabric as they go.

From there, the star fields are sent across an alleyway crowded with boxes of clothing donations to Goodwill. In this part of the room, they are carefully sewn to red and white stripes.

And then each flag is inspected, and then again meticulously reviewed.

Proenza works alongside Elmer Lujan, who is also one of many quality-control operators at the center. Both have been at the flag-making center for over a decade. Like most in the workplace, where Spanish is spoken, both are first-generation immigrants: Proenza is from Cuba, Lujan from Honduras.

The duo inspects and approves around 450 interment flags each day — around 7,000 a month. At the end of each month, the flags are shipped to a VA depot in Illinois, where they are inspected yet again.

“I love the little details in the process,” Lujan says. “There are dozens of things you have to look for in about 30 seconds. It’s an adventure every day. It doesn’t get boring.”

The flag-manufacturing operation is part of the nonprofit’s apparel manufacturing center, which employs 900 or so people. The production of interment flags earns Goodwill over $3.2 million in revenue each year, with 96 percent put toward the training, employment and job placement of people with disabilities.

Most of the other workers operate sewing machines, piecing together sections of camouflage fabric to fashion combat uniforms for each branch of the military. More than 1.5 million garments are also made here each year.

Goodwill of South Florida opened its apparel manufacturing branch in 1993 and added its flag-making operation in 1996. The nonprofit saw government contracts for military uniform and interment flag production as a way to offer employment to large numbers of people, and seized the opportunity. Since then, the branch has become the largest source of revenue for the nonprofit, second only to the income generated from Goodwill’s thrift stores.

David Landsberg, CEO of Goodwill Industries of South Florida, says the nonprofit takes pride in both its production of interment flags and in the employment of workers with disabilities; about half of Goodwill’s 3,100 employees, like Proenza, have a disability.

“It’s been great, steady work over the years, but it’s also very important work. It’s an honor to be making these flags for our veterans that have passed away,” Landsberg says.