(FORTUNE Magazine) – Golfing great Jack Nicklaus knows that setbacks are par for the course, in business and in sports. As an entrepreneur, the Golden Bear has scored as many bogeys as birdies. But after sour real estate and oil investments brought his company, Golden Bear International, close to bankruptcy in the mid-1980s, Nicklaus, 53, took a lesson from overextended corporations everywhere: Stick to the core business. Today a healthy, debt-free Golden Bear concentrates on designing golf courses and teaching golf, and brings in $50 million a year. To further sharpen his company's focus, Nicklaus decided last year to market his own line of clubs. This is a first for Nicklaus, who had endorsed MacGregor clubs for more than 20 years. When that contract expired, he was besieged by companies urging him to try -- and endorse -- their equipment. Says he: ''There were probably more clubs in my bag than there were balls on the range.'' & But Nicklaus decided he should own, not rent, his valuable name. So he joined with the owner of Toney Penna, a small clubmaker, to manufacture Nicklaus equipment. Says Nathaniel Crosby (son of Bing), who worked for Toney Penna and is president of Nicklaus Golf Equipment: ''It was a great compliment to our products that Jack asked us to dance.'' Sets cost as much as $1,800. But Nicklaus claims that an innovative design enables the golfer to hit the ball straighter and longer. Fore!