Although the most common grip among professional golfers is the overlapping or "Vardon" grip, there are some notable golfers who have used the interlocking grip. The most famous of these are Jack Nicklaus and Tiger Woods, but other professional golfers such as Tom Kite, Michelle Wie and 2011 U.S. Open champion Rory McIlroy also use the interlocking grip. You can be sure that these champions have some good reasons to use this particular grip.
In the interlocking grip for right-handed players, the pinky finger of the right hand hooks (or dovetails) around the forefinger of the left hand. This forms a physical connection that pulls the two hands tightly together. When hands using this grip wrap around a club's cushioned grip, the result is an extremely strong "joint." This physical strength is the big attraction of an interlocking grip, and its advantages manifest themselves in a variety of ways.
A common reason players choose one grip over another is their desire to create unity between their hands. When you swing your club, your wrists act as a hinge. However, if your hands become separated during the swing, each wrist can act separately and your hands can interfere with each other. This isn't a problem with an interlocking grip, which pulls the hands together so tightly that there are no gaps between any of the fingers. Nicklaus believed that the interlocking grip was "the best hand-'unitizer' going," as he put it in his book, "Golf My Way," and he never hesitated to recommend it.
Small Hand Size
Nicklaus said that he had relatively small hands, and that the interlocking grip allowed him to get a better grip with them. The more-common Vardon grip works better for players with large hands, since one of the fingers on the right hand has to wrap around the fingers of the left hand. With the interlocking grip, all of the fingers are close to the actual cushioned grip. Even the two interlocked fingers don't cause large gaps underneath.
Nicklaus also recommends the interlocking grip for players with weak hands. When your interlocked hands wrap around that cushioned grip, the club is locked in place with very little effort. It also allows even players with stronger hands to keep a firm grip without a lot of tension in the hands and forearms. Since keeping those muscles relaxed during your swing is essential to creating clubhead speed – relaxed muscles can move more quickly – an interlocking grip may help you develop more clubhead speed without losing control of the club.