"A Chorus Line" became a hit by telling of the ambitions, auditions, heartbreaks and Big Breaks of actors. But stagehands inhabit our theaters even more than actors do. And some of the stagehands' stories are even better than the actors'.

Joe and Rick Doucette -- the advance carpenter and master carpenter for "A Chorus Line," which opens tomorrow at the National Theatre -- are currently involved in a family squabble over the stage ambitions of a young newcomer that makes some of the stories in "A Chorus Line" seem mundane.

Carole Doucette, 25, wants to join the same union local as her father, Joe, 57, and brother Rick, 27. Tney support her, but the majority of the local's members are against the idea of female stagehands. And 11 out of 14 of the local's members are Doucettes or Doucette relatives. Carole is suing her own clan's local.

Doucette is one of the great family names in backstages of America. Brothers Arthur and Ernest Doucette began plying the stagehand trade in the second and third decades of the century in Haverhill, Mass., which was then a tryout town for Broadway-bound shows. The theaters of Haverhill are gone now, but the Doucette local of the union lives on there.

Actors who think the road is rough might console themselves by checking Joe Doucette's schedule. As a senior stagehand with 29 years experience, his job involves hiring crews, scouting theaters before the others arrive, making sure his shows are easing on down the road. In one two-week period recently, he was in Columbus, Louisville, Indianapolis, Atlanta, New Orleans, Dallas, Oklahoma City, Houston, Portland, Seattle, Vancouver, New Orleans again and San Diego.

"Joe gets the job done," says an official of the company that manages the road productions of "A Chorus Line." "It has been proven to me time and time again that if he says the job is going to be done, it gets done."

The job consists of more than curtain-pulling. The stage crew on "A Chorus Line," for example, must hang and focus 300 lights, which are controlled by a $150,000 computerized light board. (Doucette advises that the color patterns of "A Chorus Line" can best be appreciated from in the balcony.)

There is a sea of hemp ropes to be operated on the "fly decks" of the National's stage. There are mikes and stage sets and closed circuit TV sets

Most stagehands for a touring production are locals, and occasionally the Doucettes say they are resented for their family connections. But they have mixed feelings about those connections themselves.

Joe and Rick Doucette got their first jobs through their family. But now that they do some of the hiring, says Rick, "we get better work from people who aren't our relatives. Some of our relatives think they don't have to work as hard when they work for us."

The Doucettes do not sound like one big happy family. But there is something in their lives and their craft that has kept them remarkably together in an age when families are supposedly falling apart.

Joe tried to break away after World War II. He went to his wife's home in South Dakota and became a plumber. "After the war, nobody had any bathrooms out there," he explains. But that didn't last long. Soon it was back to Haverhill and the stage.

Rick, Joe's son, hardly ever considered any alternatives. When he was 14, he went on the road for eight weeks with Mary Martin and "Hello, Dolly!" He had to use his brother's Social Security card to qualify for the wages, but a year later he had his own union card.

Joe's uncle Arthur, at 82, continues to work in Haverhill at a family firm that builds and rents disco light shows. "The loud music kills him," reports Rick with a gleeful grin. Rick is unhappy with the old man, who is one of the most fervent opponents of Carole Doucette's attempt to join the local. "He's a pain," says Rick.

The Doucettes do not keep trouping because of the glamor of show business. They never go out front to see what it all looks like during a performance. Joe fell asleep the last time he joined the audience for one of his shows. And though Rick feels that "when the audience responds, it's not just for the actors," he adds "After the opening night, the novelty wears off."

Rick explains the difference between actors and stagehands: "We work more than they do, but we keep our mouth shut about it. Our idea is not to be visible, but just to be there. Preferably once they hire you, they don't want to hear about you."

The Doucettes aren't stagehands because it's a snap, either. From the position of an untutored audience member, "A Chorus Line" look like a backstage cinch. It appears that as long as no one shatters the mirrors on the backdrop, there isn't much to worry, about. Such appearances are deceptive.

"We put an awful lot of work into making it look like there's nothing up there," says Joe. That work has been going on at the National for nine days.

There are all those lights. And then there's a row of bulky periaktoids, three-sided devices that spin around the back of the stage during the show. On one side of the periaktoids are the "mirrors." Actually they're not mirrors; they're swaths of Mirex, a reflecting material. The Doucettes say a dancer sticks a leg through the Mirex at least once a week.

The orchestra pit for "A Chorus Line" must be covered by a chicken wire frame topped by black velour cloth. The cloth conceals the orchestra, and the chicken wire prevents any one from falling into the violins in case they can't tell the difference between the stage and the cloth.

The microphones must be carefully tested; in some theaters it's not uncommon for the chatter of police or airplaine pilots to come scratching into the earphones worn by the sound technicians. There are hundreds of little tasks to be done, or supervised, by the Doucettes and crew. Joe Doucette says, "I don't do much manual work anymore, but I do more worrying. It's great for my ulcer."

Endless traveling, family feuds, ulcers -- could the Doucettes be in it for the money?

Well, the salary for "a good road carpenter" is at least $700 a week, says someone who knows. Rick Doucette says the money isn't bad "but you have to be able to do something else. There's always a chance of the bottom falling out of the business."

The locals who serve as stagehands are frequently moonlighting. In one city, says Doucette, "if the fire whistle blows, they go out the door," as most of them are fire fighters at the station across the street.

One possible perk of stagehand life is mentioned by Rick: "It's great for a single guy," he says, because of all the young actresses. Often "there isn't much competition from the guys in the show." Rick is engaged to a dancer he met while working on "Lorelei."

On the other hand, once a stagehand is married, there isn't much time to spend at home, according to Joe Doucette. He misses that and does not plan to emulate Arthur and continue to work when he's 82.

The Doucettes simply don't romanticize their calling or their family history in any way. It's just a job, they seem to say, and Rick says he thinks a musical about stagehands "might be boring. A stagehand takes everything in black and white. You get paid or you don't get paid."

Nevertheless, the pride is there. After concluding an interview, Joedoucette catches up with the departing interviewer to make sure one thing was understood: "What you gotta remember," said Joe, "is this: My son is gonna take my place This kid is doing great."