RIVETHEAD: TALES FROM THE ASSEMBLY LINE. By Ben Hamper, Warner Books, 256 pp., $19.95YOU know that ad for Ford that shows the diligent workers passing back and forth in front of the camera, to and fro in their tasks? As they pass they look into the camera and give a half-frown, half-smile of sincerity, while they tell us that at Ford, "Quality is Job One." They are clean and neat, wearing sparkling uniforms with blue Ford insignias. We are led to believe that they are real Ford employees. And they may be. It's a good ad. Have you ever wondered why General Motors never did an ad like that? Read Ben Hamper's account of life on the assembly line and you'll know why. At the plant where Hamper learned his trade, quality was not job one. Drinking was. Boredom was job two. Trying to figure out how to double-up the work so half the workers could sleep was job three. Way down the list, after playing jokes on each other and trying all sorts of other shenanigans to relieve the stultification of the work, was building vehicles, job 47. Hamper is merciless in his narration of life at the Flint, Mich., truck and bus plant. He begins by scarifying his father as a man trapped by assembly-line work. His compatriots at the noisy, dirty, gloomy plant get only slightly better treatment. They are willing to put up with almost any indignity and stupefying boredom building Chevy Suburbans just to get the paycheck, which for the most part they spend foolishly. Hamper has little praise for anyone or anything at the plant, but he's toughest on himse lf. He is a third-generation "shoprat," which he considers third-generation hopelessness. He describes himself as having actively wasted what educational opportunities he had, and as having messed up an early marriage. But somewhere in the part of his mind not numbed by the pounding of the rivet guns in the factory or ruined by heavy drinking, he constructs a feral analysis of the economy and society in which he lives. The company regards the workers as tools and machines and the workers' opinions of themselves are not much higher. The management's abuse is answered by workers' abuses; the entire relationship becomes one of half dependency, half revenge. Leavening this lump of malice and outrage is Hamper's sense of humor. It's tough and knowing. He is a powerful writer; his eye misses nothing. He walks readers down the assembly line in the truck-cab shop, where the sparks are flying and the drills screaming, and shows the odd collection of men doing the same job over and over while the clock lags through the shift. The workers have funny nicknames, and they say and do funny things, but behind Hamper's jokes and sarcasm is sadness on a good day and horro r most other days. What saves him is the only thing he developed a talent for in high school: writing. He begins writing record reviews of rock-music groups for the local alternative paper, the Flint Voice. The editor is Michael Moore, who later produced and starred in the film "Roger and Me." A bond forms between them based on Hamper's emerging talent and Moore's emerging position as the voice of the working-class American that industry is leaving behind. You have to wonder what someone like Roger Smith or the other General Motors management thinks or learns when they read about life on the line. The place, by Hamper's account reeks of mismanagement and inefficiency. At one point the bosses put up a huge electric message signboard over the rivet line, and one day Hamper comes in to find the slogan "Squeezing Rivets is Fun!" blinking on and off, as if this would improve the mood. Hamper is curious, along with everyone else who thinks about it, about why the American corporations, faced with the absolute superiority of the imported products, did not change their production methods sooner to reflect the full potential of workers as human beings. Smith and his ilk stayed with the satanic mills method long after their product had sagged behind, and if you've ever driven a Suburban you know what I mean. Hamper's health, mental and physical, sagged as well. He quit GM, and shortly thereafter the Flint plant and others closed - in keeping with Smith's master plan, a plan that makes former GM chairman Charlie Wilson look positively avuncular. Hamper now writes and recuperates. This book is a good read, but it's also valuable because it shows a part of the problem the United States now faces. With nothing but profits in mind, the insidious Smith - who was, after all, an accountant, not an engineer like the late Mr. Honda - treated people as machines fueled by money. The vacant plants of the Midwest are the legacy of this policy, to say nothing of the collective shame resulting from the drop in US manufacturing quality. Of course it might be said that Hamper contributed to the p roblem, but he comes out of the book as knowing more about the problems than the bosses. Smith doesn't care about his product, and neither do his workers. All either cares about is money. Which is too bad, because I always thought that designing and making cars would be rather fun. From early youth I pictured the job pretty much as it appears in the aforementioned Ford ad. I wonder now if it's really like that. Of course, I haven't driven a Ford lately.