Violinist Elmar Oliveira, who will perform Friday at the Library of Congress, is best known as a world-class soloist who won the Tchaikovsky Competition. But he's also one of those rare virtuosos who can fix his own fiddle.

"I have some expertise in it," he said the other day. "I'm often doing things like setting posts, making bridges and cleaning the fingerboard. I wouldn't attempt a major restoration on my fiddle." It's a 1781-vintage Guadagnini, an instrument on a par with a Stradivarius or Guarneri. "I've never made a complete violin, but at one time or another, I've made virtually every part of a violin."

Oliveira, 33, credits his skills to his father, Jose, a carpenter who gave him his first fiddle, a homemade model, when he was a mere prodigy of 9 in Naugatuck, Conn. He began to dabble in his father's shop--"just for fun," he said.

The violinist added, though, that he hasn't made anything ambitious since 1978, when he won the prestigious gold medal in Moscow and his schedule promptly increased from 20 to 100 concerts a year.

"There's just no time," Oliveira said. "The last thing I made was a scroll"--the part of the violin protruding from his hand in the picture below.