Roused by the throaty roar of nearly 400 motorcycles, Boeing's largest union put on a festive show of unity yesterday at a SeaTac park near where negotiations on a new labor agreement with the company entered the home stretch.

Sporting black T-shirts urging Boeing to "Do the Right Thing," rank-and-file members of the International Association of Machinists (IAM), District 751, said they have been saving money and are ready to walk off the job if they are not happy with an offer Boeing will put on the table next week.

Negotiators for Boeing and the Machinists have been holding round-the-clock talks at the Doubletree Hotel in SeaTac since last Monday. The union's contract expires just after midnight Sept. 2.

Few details from the talks have drifted to the factory floor, so the likelihood of a strike will be hard to gauge until the Machinists see Boeing's "best-and-final" offer Aug. 30.

The union will vote Sept. 1 on whether to accept the offer.

The members also will vote on whether to go on strike. If the contract is rejected, a two-thirds majority is necessary to authorize a strike.

"It's one of the quietest negotiations we've ever had," said Curt White, 52, who works at the delivery center at Boeing Field in Seattle.

"We've got nothing to go on until we see the contract," said Scott Anacker, 52, a research-and-development mechanic at Plant 2 in Seattle.

White, Anacker and many of the other gray-haired Machinists in the crowd yesterday reinforced their union leaders' assertions that pensions and health care are the top concerns for the union. The average age of the membership exceeds 50.

Factory service worker Marilyn Ali of Lake City, accompanied by her daughter and granddaughter, held a sign that read, "Let us retire with dignity $$$."

Drawn by sunny skies, free hot dogs and a chance to send Boeing a message, roughly 4,000 Machinists and their families massed at the Doubletree yesterday afternoon.

After speeches from Seattle Mayor Greg Nickels, King County Executive Ron Sims and state House Speaker Frank Chopp, D-Seattle, the throng accompanied the massive motorcycle brigade to a rally on a lawn overlooking sun-bleached Angle Lake a half-mile away.

There, Mark Blondin, president of the local union, and Dick Schneider, national aerospace coordinator for IAM headquarters in Washington, D.C., encouraged members to stick together and to let management know that union negotiators have unyielding support from the rank and file.

"The goal of your union is that you do not take a step back in your standard of living when you go into your retirement years," Blondin said.

Currently, retiring Machinists receive $60 per month for each year they have worked for the company. Workers are eligible for full pension benefits at 62.

Blondin noted that he, Schneider and the five subcommittees meeting daily with Boeing at the Doubletree are working on a range of other issues, from limiting employee payouts for health care to increasing job security, even as Boeing is sending more and more work overseas.

"Is there a reason that The Boeing Company cannot guarantee us that we're gonna be here in three years?" Blondin said.

"Do you want your job in three years? Is there any reason that they can't guarantee security at least for the duration of this agreement? I don't think so."

Dave Herrick, 47, who works with Anacker at Plant 2, said Machinists have implemented lean manufacturing techniques and other production changes that have made Boeing more successful in the past two years.

"Everybody's worked to make [Boeing] more efficient in the way they wanted to be more efficient," Herrick said.

Now, he says, it's time for the company to reward the union's loyalty.

Yesterday, Boeing spokesman Charles Bickers said only that the company is pushing for a contract that is "going to help us be competitive."

"Winning new business is the way that we create and sustain jobs going forward," Bickers said.

The Associated Press contributed to this report.

David Bowermaster: 206-464-2724 or dbowermaster@seattletimes.com

Seung Hwa Hong: 206-464-3347 or ihong@seattletimes.com