Thanks to his crusty style, his occasional well-placed obscenities and his tough-minded stance at the bargaining table, Donald H. Weinberg has become the man the city's labor unions love to hate.

"My role is to take the heat," said Weinberg, the District government's chief labor negotiator, "When you have to say 'no' to people, it causes anxiety. But we are here to bargain. It is not a giveaway program."

Weinberg, 55, the $63,000-a-year chief of the D.C. Office of Labor Relations and Collective Bargaining, has played the role of Mayor Marion Barry's lightning rod, attracting the anger of municipal employe unions that might otherwise be directed at Barry.

Growing anger toward Weinberg -- and toward Barry -- led to an unprecedented meeting last week among unions representing most of the government's 30,000 employes. They met to form a coalition to discuss ways to exert stronger pressure on the Barry administration and to deal with Weinberg during continuing city labor talks that have been described as the toughest and most acrimonious in recent memory.

"When Weinberg's name comes up at AFL-CIO meetings, it sets off a chain reaction . . . . People start telling their Weinberg horror stories," said Joslyn N. Williams, president of the Metropolitan Washington Council of the AFL-CIO.

Weinberg, in more than 20 years in D.C. government, has mediated, negotiated, cajoled and finessed his way through bitter strikes by prison guards, sanitation workers and other municipal employes, and he has handled sensitive issues such as affirmative action for Barry and his predecessor, Walter Washington.

The Weinberg war stories usually accuse him of refusing to bargain in good faith, storming away from the negotiating table, threatening various political reprisals, and, inevitably, letting fly with an occasional expletive that might question a union negotiator's family heritage.

His theatrical negotiating style appears to be part of his emotional nature and part of a calculated strategy accumulated in 25 years as a labor negotiator for the District, for Prince George's County, for a Philadelphia steel company, and briefly as a consultant for labor and management.

"I am an emoter. They say I get too hot under the collar, but I am really pretty controlled. I don't ever lose it," Weinberg said.

"I once got told by a union that when I sat there placidly they were disappointed . . . . They expect a show."

"Weinberg is . . . well, he is Weinberg. He is a tough negotiator. When you appear before him, you have to do your homework or he will cut you to ribbons," said Kenneth Cox, vice president of Local 36 of the International Association of Fire Fighters.

In response to criticisms about his abrasive style, Weinberg said, "I never said I was lovable. I said I was fair and reasonable."

Others do not always agree. The city was charged with unfair labor practices last October when it cut off workers' dental and optical benefits after the city's labor contract expired. The action, regarded as a pressure tactic to force unions to settle, was ruled illegal by the D.C. Public Employee Relations Board.

In another reflection of tough times at the bargaining table, the employe board last week -- for the first time in city history -- ordered binding arbitration to resolve a contract dispute. Board officials said that relations between the city and the 3,300-member Fraternal Order of Police were so strained that a third party would have to resolve the eight-month impasse over wages and benefits.

Weinberg, noting that Barry has enjoyed good relations with labor unions, describes the mayor as "one of the strongest advocates of collective bargaining I have ever worked for . . . . But we are paid to manage the government, and we don't give away our right to manage, and we don't give away things at the bargaining table."

In 1982, during election-year bargaining, the city agreed to 21 percent pay raises over three years in what was widely regarded as a sweetheart deal by Barry for union political support. But this time, the city gave roughly half that much in the pay negotiations concluded last October. Separate talks on sick leave, grievance procedures and other thorny issues are continuing.

Over the years, as city workers gained full collective bargaining rights in 1980 and labor issues grew more complex, Weinberg's staff has grown to 15 and his tasks have become larger and more controversial.

"When you deal with police and fire departments, a mistake at the bargaining table can cost you millions of dollars by allowing overtime pay when you shouldn't," Weinberg said, "and the issues get terribly emotional. When you talk about things like manning the fire department, you are dealing with potential injuries and deaths."

Weinberg, who underwent open-heart surgery 10 years ago, likes to retreat from work place stress by biking, hiking and mountain climbing, often with his wife of 33 years, Joan, an economist.

Gwen Hemphill, director of the office of labor liaison that Barry created last year to deal with union officials, spends much of her time taking flak about Weinberg. "Don has a job to do and he does it," Hemphill said, "The unions will not be happy all the time, and the city will not always be happy. That's the way it goes."