Ten months into a strike that many labor leaders lament as ill-advised, union printers, press operators and mailers at the Chicago Tribune are further from winning a new contract than the day they walked out last July. The Tribune, the nation's fourth-largest newspaper and the Midwest's leading editorial voice, is thriving and does not intend to rehire the strikers.

The paper's management, hanging tough, has hired a Tennessee law firm with a reputation for union-busting, refused mediation offers from the governor and the mayor and staffed the composing room, pressrooms and mail room with nonunion workers. The replacements include many women and minorities, abruptly ending a nearly hereditary lock on Tribune production jobs once held by the heavily white craft union locals.

Despite tenacious picketing, unusual unity and determined leafleting for community support, the nearly 1,000 striking production workers have not overcome the damage done on the strike's first day when Teamsters union drivers crossed the picket lines.

They have continued driving the Tribune's familiar white-and-blue trucks, delivering "the product" to 763,000 daily and 1.1 million Sunday readers.

The dispute centers on union opposition to management attempts to reassign printers from jobs made obsolete by computers. Contract talks had dragged on for about 2 1/2 years without settlement. Because the fight concerns labor-saving technology and Chicago remains a bastion of blue-collar power, publishers elsewhere are watching the face-off with interest.

At the annual stockholders' meeting last month, the paper's parent media company announced record profits of $241 million for 1985 and predicted even better results for 1986. In Fortune's list of the nation's 500 largest corporations, the Tribune Co. moved to 187th place in sales in 1985, up 22 places from 1984.

The paper has made sparing comment about the strike. "Our position is that, in general, mediation is helpful when the issues are not clear-cut," Tribune spokeswoman Ruthellyn Roguski said. "But in this case, the issues are very clear cut."

Roguski said the production crews now "are very much reflective of Chicago's population" in percentage of women and minorities. The city is more than 50 percent black and Hispanic. "I can tell you that all of the strikers except 63 positions in the composing room were permanently replaced," she said. "Negotiations continue on a regular basis."

The 63 got their jobs back after the printers union made an unconditional offer to return to work. Under the law, the strikers were not entitled to their old jobs back but were given preference for vacancies. The pressmen also have offered to come back, but none have returned because the company says it has no vacancies at present.

Morale remains strong among the strikers, who are mostly middle-aged white men with years of experience at the Tribune. They say they are embittered by its tough tactics.

"It's strictly union-busting," said Bill Warmbold, a 58-year-old mailer. "I've been on other strikes, but nothing like this." He and other strikers accuse the paper of bringing in "scab" production personnel trained at Southern Production Program Inc., an Oklahoma City facility operated by about 170 publishers to train nonunion employes.

But an SPPI spokesman said Southern Production had done no training for the Tribune "in a very long period of time."

Strikers' spirits were buoyed when the regional director of the National Labor Relations Board upheld one of several complaints filed by the union alleging unfair labor practices by the newspaper. But the finding is preliminary and has not been tested in court. Should they ultimately win on the issue, the strikers could be eligible for considerable back pay.

Meanwhile, 63 striking printers have returned to the paper at management's invitation, crossing the picket lines they once manned with their still-striking colleagues. Some strikers applaud this as proof that the paper needs their expertise. Others find little solace in the fact that their colleagues are back at work while they are still working shifts on the picket lines.

Many similar union-management battles over staffing rules and technology have been fought elsewhere in the newspaper industry in the past 20 years -- most of them won by management, changing the balance of power in the entire industry. One of the most famous took place at The Washington Post in 1975-76, when a violent walkout by pressmen led to a long strike. Like the Tribune, The Post kept publishing with nonunion labor. Pressmen who struck The Post never returned to work, and the paper's three press rooms are operated by nonunion workers.

The Tribune strike could become a similar industry milestone, newspaper executives say. Big newspaper company stocks have soared in the ongoing bull market on Wall Street, encouraged in part by the soaring value of big-city dailies as reflected in recent sales, but publishers see themselves as especially vulnerable to local labor costs.

"We're not like other businesses that can move out of town or out of the country if labor gets too high," one big-city publisher said. "We're rooted in the city where we publish."

"If the Tribune can win this one in a hard-rock blue-collar town like Chicago, there's hope for all of us," said another.

For that reason, union leaders here and around the country say they regret that the strike took place. They doubt that it can achieve much considering the financial hardships for the strikers, who may never find new jobs paying the $25,000 to $30,000 they were taking home each year from the Tribune.

"It's hard to beat a newspaper these days if you can't shut it down," said labor leader George E. McDonald, director of New York's Allied Printing Trades Council and head of a newspaper craft-union coalition with a formidable record of bargaining success. "You've got to get the paper down."

Last summer's walkout here held little promise of that. The strike occurred in the aftermath of a bitter leadership struggle within the International Typographical Union (ITU) over what many members believed would strengthen the union's future bargaining power: a merger with the International Brotherhood of Teamsters. ITU leaders opposed to the merger won control, and the union's membership subsequently defeated the Teamster merger proposal by a substantial margin.

Although the vote by mail ballot was under way and had not been tallied at the time, the merger opponents' rise to power, led by ITU President Robert McMichen, had angered Teamsters President Jackie Presser.

"It's too bad they [the striking unions] didn't have it together and [hadn't] checked out everything ahead of time," McDonald said. His comment was echoed by several labor leaders here who asked that their names not be used.

John Morton, a newspaper industry analyst for Lynch, Jones & Ryan, a Washington securities firm, said, "We . . . have believed from the start that the unions made a grievous tactical error, and they likely will never get back in the door. So long as papers control their own distribution, unions don't have the power."

Several labor leaders said last year's strike of Philadelphia newspapers underscored that point. Drivers' contracts expired the same day as other unions' contracts. Unable to deliver, the papers ceased publication, and the strike ended with a settlement after 46 days.

Even Dennis Boyle, coordinator for the strike unity council, conceded, "The easiest way to end the strike early would be to stop delivery. If they [the Teamsters] had gone out, we'd have never forgotten them. Well, they didn't go out -- and we'll never forget them."

The ITU is now exploring a possible merger with the Graphics Communications International Union, which includes the mailers and the pressmen. But even a merger with that union would be unlikely to effect the protracted Tribune strike.

Recent audit reports show that the Tribune and its competitor, the Chicago Sun-Times, declined in circulation in the six months ending March 31 compared with a year earlier. Management at both papers blamed the reductions on discontinuing their daily afternoon editions to cut costs.

Tribune average daily circulation was 760,000, down 15,000 from the same period a year earlier, and the Sun-Times fell 7,300 to 632,000. Tribune Sunday circulation was 1.1 million, off 2,500 from a year earlier and 499,000 ahead of the Sun-Times.

Meanwhile, the picket lines that went up July 18 have taken on a stubborn permanence in front of the landmark gothic Tribune Tower on Michigan Avenue and at the paper's sprawling printing and distribution center on Grand Avenue several blocks to the west.

At the unity council in a vacant Division Street factory building on the North Side, organizers contend that they are slowly making headway against the Tribune and that community support for them is increasing. The members belong to the Web Pressmen's Local No. 7, Chicago Typographical Local No. 16, and Mailers' Local No. 2.

"If the barometer of a strike is the bargaining table, then there's no progress at all in bargaining," coordinator Boyle said. Tribune spokeswoman Roguski pointed out that nine other unions, including the Teamsters, are working at the paper and that two of them have signed new contracts since the strike began. Tribune journalists are not covered by a union contract.

Veteran New York strike mediator Theodore W. Kheel, who at the request of New York printers met with labor and management here last fall in a fruitless attempt to prompt some movement, criticizes both sides.

"This is a situation that cries out for some outside assistance," Kheel said. "But I think the Tribune thinks they have this one won. What would you do? They're putting out a paper at half the cost and doing just fine."

He said he finds management's stance objectionable because "these same unions in New York cooperated" with a request from the Tribune to reduce production costs at the Tribune-owned New York Daily News in an effort to end the tabloid's red ink several years ago.

"Without their help, the company would not have been able to stop the bleeding," Kheel said. A subsequent Tribune public stock issue was a great success, he said. "Those unions made [Tribune President Stanton R.] Cook and other [executives] multimillionaires. The cooperation was the most important thing in the life of the Tribune Company then."

But, he added, "This is not to say the [Chicago] unions have handled themselves with finesse. They've acted like a bunch of jerks."

Ed Brabec, president of the Chicago Federation of Labor, said the negotations and the dispute "don't seem to be going anyplace. It's a very, very difficult situation. When you settle one point [in bargaining sessions], you come back the next time and it's off the board. You've got to start all over. You're never going from the same spot."

Looming ahead is the likelihood of a management attempt to decertify the striking unions after the walkout is a year old. Such a move has become familiar to the ITU as technological change continues in composing rooms.

The strikers console themselves with the belief that the Tribune has had to hire far more workers to get the paper out. "Press room crew size is 12 or 13 people," Boyle said. "It used to be seven or eight. And our argument on minorities is that, sure, they integrated the work force. But first, they had to have a strike, and they brought the [pay] scale down to a lower level."

Roguski explains it differently. "Productivity is substantially higher now," she said.

The irony," Kheel said, "is that the Tribune Co. is capitalizing now on its equal employment. But the situation that existed was created by the Tribune and the unions together. They agreed on who was hired. It was done with the consent of the Trib at a time when they were totally disinterested in these issues."

Replied Roguski, "I don't think there would be any benefit in commenting on that. It's his opinion."

Whatever the outcome, the strikers see an unpleasant, uncertain future.

"My future is very undecided," Warmbold said. "At 58 years of age, whatever happens now has to come by chance. Over the years, you knew the people you worked with. They worked their way up. Friends. Now, one day you're working, and the next day, you're walking . . . . It's kind of a scary feeling."