Angle of Contact - the angle at which
your putterface contacts the ball.
Your putter rises on the backstroke and rises again in the forward stroke. The sweetspot of your putter should meet the equator of your ball at impact.
If the approach of your putter into the ball is too steep, or too shallow, you will have trouble with both your direction and distance control.
When you swing your putter, it rises on the backstroke and again in the forward stroke. At the bottom of its arc your putter will be closest to the ground.
In a neutral setup with your weight evenly distributed between your feet, the lowest part of the arc will be in the centre of your stance.
On the green your ball settles in a slight depression, no matter how tightly mown the grass is. To help your ball out of the depression so it rolls on top of the grass, your putter is designed with about three to four degrees of loft.
At the moment of impact it is important for you to maintain this same degree of loft to put a smooth roll on the ball. Too little loft will jam your ball into the turf while too much loft will cause it to become airborne, much like a chip. Both situations interfere with consistent direction and distance control.
The ideal angle of contact matches the sweetspot of your putter with the equator of the ball. To achieve this match, your ball position must be correctly located between your feet. Too far back and you will hit down on the ball with the top half of your putter. Too far forward and you will hit up on the ball with the bottom half of your putter.
The standard face height of putters is one inch and this puts the sweetspot vertically at a height of half an inch. A golf ball is 1.680 inches in diameter with its equator at a height around 0.84 inches.
If you place your putter against the ball, the sweetspot of your putter will be lower than the equator of the ball.
For this reason most putting coaches recommend that you position your ball slightly forward of centre.
By placing your ball just forward of the bottom of your putting arc, you allow your putter to make contact with the ball as your putter starts to rise. If you prefer, as some golfers do, to centre your ball in your stance, you should either lift your putter as you start your backstroke or hover it about the ground during your setup.
There is no ball position that is wrong, other than to say that no-one recommends placing your ball back of the centre line. Where you place your ball will depend on how you distribute your weight, the vertical alignment of your putter shaft, and if you use a forward press on takeaway that delofts your putter.
There is only one rule to remember:
For solid contact position your ball so that the angle of contact allows the sweetspot of your putter to contact your ball exactly at its equator.
1 = www.golfdigest.com
2 = www.straightaimgolf.com