It's 8 oClock tonight and we have arrived home. Switch off the brain, switch on the TV. The Republican convention can wait, as can the American Express bill, the garden, the softball game, the bulging briefcase, the dinner dishes, the Popsicle-stained children, the poems of Coleridge, the cleaning of the refrigerator and the naggingly obligatory phone call to Aunt Hilda, whose 37th wedding anniversary is more or less today. You wish to reach out and not touch someone. Understood. A-OK. Perfectly normal July behavior.

Time for "Roughnecks" on Channel 5, reputed to be a sprawling two-part, four-hour mini-series about a crew of crack, two-fisted oil-well drillers and their search for geothermal energy on a Southwestern ranch. We know what to expect: that familiar formula of ambition and lust that leads a collection of cads, naifs, and predestined inheritors through a poster-painted dramatic landscape riddled with crises and commercials. Sounds perfect.

Unfortunately, ready as we are for "Roughnecks," "Roughnecks" is not ready for us. Lower your standards as you will, this well of schlock is dry. Rattlesnake Productions and Metromedia Producers Corp, have made the unforgivable mistake of calculating the lowest common denominator and getting the answer wrong.

Look, fellas, we want a smidgeon of verisimilitude. Those roughnecks all have new shirts on. Their jeans have never even been washed. Here they are, working in the mud up to their eyebrows trying to extract geothermal energy from a ranch populated by evil, progress-hating cowboys, and they look like pages 407 through 418 of the Sears catalogue. So do the cowboys.

We're all for the attempt to drill into "devil's brew," with the danger of a substantial explosion of methane gas, so why don't you do it? Why is everyone standing around talking about the weather, playing dominoes, ordering another beer? Why doesn't anything ever seem to happen?

Cathy Lee Crosby, Ana Alicia and Vera Miles may be very pretty, and Sam Melville and Stephen McHattie may be dashingly handsome, but how come they seem to be reading their lines off of cue-cards? By the way -- that scene in which Harry Morgan is introduced sitting in a sudsy bathtub smoking a cigar? We've seen it 112 times.

Okay, Wilford Brimley was terrific as the walrus-like company man in "The China Syndrome." But casting him as a walrus this time doesn't seem enough. Know what we mean?

Look, fellas, you know what usually keeps us interested? it's that just before each commercial, the story sort of gets exciting. It sorts of wells up, and so do we. But when your commercial breaks arrive, they usually leave some roughneck just standing there with his hands in his pockets. Makes you sort of want to switch channels. Even to Detroit.

Is this the first mini-series any of you have ever worked on?Have you ever seen one? What did you do before you made this little number -- blow insulation into the walls of houses?

The question comes up because at the end of Part I tonight at 10 o'clock, in an attempt to get us to tune in tomorrow night for the concluding two-hour portion, you apparently kill off the bad guy. That's not usually the way it's done. Did you ever see an episode of Flash Gordon end with Ming the Merciless in mortal danger?

It's not that we're ungrateful for Part I of this summertime diversion gentlemen of Rattlesnake and Metromedia. It's probably the only possible program that could make the Republican National Convention look like drama of high suspense. And you know how fickle we television audiences are.