For a quarter -century, the message from the job -market has been loud and clear. Avoid traditional blue-collar work. Go to college. Scramble for a -foothold in the service industry elite, where, unions and seniority mean little and adaptability is the most prized talent. If you are really ambitious and prepared to risk your life savings, start your own business.

But don't try telling that to Lynn Hummel, a former bank clerk who tripled her earnings by becoming a longshoreman in Los Angeles. Or to Eugene Vasser, who says he makes "substantially more than $100,000 a year working for a welding equipment maker in Cleveland that pays according to individual productivity. Or to Herman Aguirre, a Colombian immigrant who worked his way up from janitor to master jewelry maker in a New York City loft factory and now commands a six-figure income.

This handful of redwoods, of course, should not be mistaken for the forest. The median annual earnings of male high school graduates in 1995 were just $29,000, down by one fifth since 1976 after taking inflation into account and barely 60 percent of those of their counterparts with college credentials. The earnings data for women show the trend, too: the average pay for those with high school diplomas was $19,856 in 1995, down 5 percent in 20 years and. just 59 percent of the earnings of college graduates.

Nonetheless, in the right jobs and under the right circumstances, "there's still a pot of gold for blue-collar workers at the end of an increasingly slender rainbow," said Daniel Hamermesh, an economist at the University of Texas.

For some, success turns on working longer and harder. For others, high pay comes with highly valued skills not taught in college. And for still others it is a matter of breaking into the club - of joining one of the small, powerful unions that vault semiskilled workers into .the upper middle class. Even if only a handful can follow these paths the lack of earnings opportunities for people who work with their hands makes every case worthy of a close look.

Consider Ms Hummel, who was a 29-year old, divorced mother of a chronically ill child and had no health- insurance back in 1984, when she first heard about job openings at the Port of Los Angeles.

"All I knew - and needed to know - was that it paid well and came with medical benefits," she recalled.

Along with thousands of others, she applied for a place on the International Longshoremen's and Warehousemen's Union roster of "casuals" - people who are eligible for employment on the wharves at -union scale when seasonal demand exceeds the supply of union members. Five years and hundreds of phone calls later, she was allowed to take a test to prove she had the dexterity and strength for the work.

In an era when few women worked at the sprawling port, the initiation was rough. "The men called us tramps," she remembered. Worse, there was little formal training and few colleagues were willing to show her the ropes in a risky job involving heavy equipment. But she persisted eventually quitting her full-time job at Coast Federal Savings so she could accumulate enough hours to qualify for full union membership.

Ms. Hummel, now 43, made $81,000 last year operating the oversized forklifts that stack the big steel containers and instructing casuals to maneuver trailer trucks through tile maze of dockside obstacles. Teaching - especially teaching the women trying to break into the union - is obviously a labor of love as well as money. "You have to remember where you came from," she said.

Most longshoremen make considerably more than Ms. Hummel: last year, full-time workers at West Coast ports averaged $97,000. Unionized clerks working comparable hours averaged $114,000, while foremen averaged $148,000.

Ms. Hummel has opted for regular hours, avoiding better-paid weekend and night work. And she can afford to. Apart from shoes ("1 have a thing for Joan and David"), sport utility vehicles (she drives a Chevy Tahoe) and winter vacations in Mexico, her tastes are modest. Besides, she is now married to a longshoreman, and her daughter, who has grown out of her child-hood asthma, has managed to join the union, too.

Loading and unloading ships is dirty and fatiguing work. "Just try attaching a 72-pound lashing bar to a container when it's raining and windy," Ms. Hummel said.

But mining and bricklaying are difficult jobs, too, though median annual earnings in those two fields barely top $35,000. Longshoremen earn much more for one obvious reason: their union controls the supply of labor at every West Coast port.

There is a less obvious reason, too - what Lawrence Katz, an economist at Harvard, calls "the importance of being unimportant." While the $700 million paid to West Coast longshoremen in - 1996 was hardly small change, their wages represent only a tiny fraction of the total cost of moving hundreds of billions of dollars worth - of international cargo from factory to consumer. Accordingly, shippers are prepared to pay the premium needed to have the work done.

Lincoln is America's largest specialized manufacturer of welding equipment, with sales of $1.16 billion in 1997. But the reason that the company's name is familiar to almost every business school student is its' longstanding commitment to linking pay to both individual productivity and the profitability of the corporation.

Millions of American workers, from sales representatives to truckers, are paid according to their out- put. Many others collect annual bonuses tied to their employers' profits or revenues. But Lincoln is nearly unique among large American companies, paying all shop-floor workers according to a formula based on how much they produce, how much they contribute to the team effort and how much the. company earns.

Mr. Vasser, who has been at Lincoln Electric for 25 years, ranks in the top 10 percent in pay at the company. But all 3,400 Lincoln Electric shop-floor workers do well, with wages averaging $58,000 in 1995 (the last year for which the company would provide data), not counting the value of their rich package of medical, vacation and retirement benefits. And the company, which is publicly traded, hardly operates as a charity. Last year's net income of $85 million represented a healthy 20 percent return on shareholder equity in a very competitive industry.

Is there a lesson here for companies fighting tooth and nail to keep down wages - or for the average production line worker making $13 an hour? Lincoln Electric thinks so. It publishes how-to books on incentive pay and invites anyone with a serious interest in the subject to study how the company manages to pay twice as much as competitors do while remaining a low cost producer of welding machinery