One of the leaders in the U.S. Open golf tournament is Bob Clampett, who was seven weeks old when Arnold Palmer won the Open here in 1960. Clampett shot a 70 yesterday, doing it with a series of long putts. Certainly, he was nervous. "There's never been a person who stood on the first tee at the Open and was as calm as a duck," Clampettt said. Neither has a duck ever beaten Arnold Palmer by six shots.

On the occasion of his sentimental return to the scene of the victory that made him unforgettable, Palmer shot a 76. Time passes. Palmer is 48 now and he's gray and there's a paunch below where the fire of greatness once burned. The kid Clampett was in diapers in 1960 and now he's 18 years old and he plays golf fearlessly. Palmer can't make a putt, Clampett can't miss one.

Come to the 18th green, where Clampett stands over a 15-foot putt. He's a little guy, maybe 5-foot-9 and 140 pounds. A California who's now a freshman at Brigham Young University, Clampett is the skinny blond type first made famous by Johnny Miller. Over this 15-foot putt, Clampett resembles nothing if not a high school caddy on summer vacation.

Until he strokes the putt.

The putting move is soft.Palmer jerks the putter, as if anxious to tap the ball before it jumps to life and runs into a lake. Clampett is 18 and the bill collectors have never bothered him and he thinks of one thing only: making putts. When you're 18, putting is easy. At 48, putting can be public torture.

So Clampett putts that soft stroke on the ball, needing the 15-footer to save a par on the most difficult hole at Cherry Hills Country Club. Defending champion Hubert Green made a double bogey there, Tom Kite a triple, Dick Osberg a quadruple. And Bob Clampett rolls in the putt for a par.

As the ball disappears, Clampett thrusts his arms strongly overhead in celebration, drops his putter across his golf bag and walks off the green, leaving his caddy to retrieve the ball from the cup. That's the way tournament winners do it, and Clampett is practicing for the hole.

Every U.S. Open produces a fresh face the first day or two. A fellow named Marty Fleckman never got over it. Fleckman, then an amateur, led the 1967 tournament after three rounds. The last day, he put his very first shot under a tree, went on to shoot 80 and now is lost in the dreary world of pros who work in second-rung turnaments, scraping for a hundred dollars here and there. And where have you gone, Rives McBee?

Two years ago, the face belonged to another Brigham Young University golfer, a wide-eyed kid named Mike Reid, who began with a 67. The next day, he hit a shot into a swimming pool. An 81 was born. Now it's Bob Clampett's turn and he confessed that thoughts of Mike Reid crossed his consciousness during yesterday's round - and after it.

Through 10 holes, Clampett was one over par. He reached the 594-yard 11th with a driver and a three-wood, two-putting for a birdie. He also made birdie at the 12th, hitting his five-iron tee shot 30 feet from the cup and making that putt.

That put him one under par and there it was, his name, in big capital letters, CLAMPETT, going up on the scoreboards around the course. "Right then I could relate to what Mike went through," Clampett said. If a golfer is without the calm of a duck at the first tee, how is an 18-year-old college freshman supposed to act when he's leading the U.S. Open?

Clampett did an extraordinary thing. Even as the terminal Open shakes began their work of destruction, Clampett became a putter beyond compare. He drove the ball into jail, but escaped with the picklock of his putter.

On the next four holes, from 13 through 16, Clampett neither drove the ball into the fairway nor hit a green in the allotted number of shots. Yet he made another 30-footer, the likes of which Arnold Palmer once willed into the hole but now couldn't make if the cup were a canyon.

At the 17th, Clampett saved par with an eight-iron shot out of a fairway bunker. At the 18th, he droved badly into the rough on the 480-yard hole, came out weakly and needed that 15-footer for par. A piece of cake.

A golfer since he was 10, a junior champion at 15, the winner of Houston's All-American Invitational college tournament, Bob Clampett wants to be a touring pro. He was an aging 12 when he decided that. They played the 1972 Open at Pebble Beach, about four miles from his home, and he worked shagging practice balls for Gary Player and Dave Stockton. "They really inspired me," Clampett said yesterday.

He twiced failed to qualify for the Open, and at tee time yesterday he came down with a sudden case of the panics. As he started toward the tee at a stroll, he saw no one there.No one down the fairway, either. The casual stroll became a mad sprint.

"Oh, my God, I've missed my tee time," he thought. Later he could smile at the memory, for, as it happened, he arrived 90 seconds early. "It's really important," he said, "to not miss your tee time in your first Open."

Happily for his nerves, Clampett struck a perfect one-iron drive, dropped a nine-iron 16 feet from the hole and, naturally, made the putt for a birdie. Palmer, who was 30 when Clampett first put an overlapping grip on a baby bottle, needed two putts from 20 feet for a par at that first hole.

"I met Mr. Palmer once," Clampett said, eyes atwinkle, "I needed a ride from Pebble Beach back to the hotel. So I went up to him and said (here in a little boy's quivering voice), 'Mr. Palmer, could I please get a ride back?'"

Palmer took the kid to the hotel. "I sat back in a corner of the car and pretended nobody saw me," Clampett said yesterday.

Palmer doesn't remember the skinny blond kid and he hasn't seen him play this week. Time passes. Clampett used 28 putts, four of them longer than 15 feet. Plamer wouldn't count up his putts for inquiring newspapermen, saying only, "I didnt make one longer than two feet."