Without question, the most frequent putter fitting problem observed at the Academy is the negative influence of a poorly installed putter grip with a flat surface. If the flat portion of the grip is not perpendicular to the putter face or at the very least does not match the perception of the player, any number of problems can occur.
This is an example of a player with a poorly installed grip. On five measured strokes we see this player has a consistent and successful ability to aim the putter. However, at impact the putter is consistently to the right of the intended target.
Upon inspection, we found when the flat portion of his grip was placed in horizontal position, the putter face was open to vertical just about the same amount as we found it open at impact. So how does this happen.
This player aims the putter visually. Using the line on the putter and matching it to a line on the ball. The result as we saw was very effective. Once he swings the putter away from the ball feel takes over and he swings the putter to a position where his thumbs are on top of the shaft. This opened the face and he maintained this postion through the rest of his stoke.
The best way to see how a flat sided grip affects your stroke is to try a round grip. The hands are placed on the putter matching where the putter is aimed. When the putter swings it does so without influence from the grip. You will find the comparision of the your stroke with a flat grip to a round quite educational and thought provoking.