The Putting Arc is an Ellipse

	The Putting Arc ... is an Ellipse The Putting Arc works because it guides the putter head in pure planar rotation about an axis which passes through the golfer's spine, at the T3 vertebrae between the shoulders (the dashed line in fig. 1). This means that the hands, wrists, elbows and shoulders all stay connected throughout the putting stroke. The Putting Arc has radial lines on its top. This important feature shows the correct clubface alignment at each point in the stroke. This alignment is just as important as the clubhead path
Mathematically speaking the putter head actually moves in a perfect circle. But since the axis of rotation is inclined relative to the putting surface the putter head motion projects onto putting surface as an ellipse. (Teaching pros if you don't believe us, contact us about 'Iron Archie', a robot demonstrator/teaching aid that proves The Putting Arc concept). This ellipse (the light colored shape in fig. 2) is the mathematical basis for The Putting Arc.
	The actual dimensions of The Putting Arc ellipse are defined by the location of the center of rotation of the putter head. (This point is located on the golfers spine at the T3 vertebrae.) Suprisingly, the dimensions of The Putting Arc ellipse are similar for all average size golfers. There are only a few thousandths of an inch difference in ideal shape of The Putting Arc for a 5'4" golfer and a 6'2" golfer (assuming a typical putting stance). For golfers with unconventional stances or people who simply want an ideal match we can generate a custom Putting Arc. The custom Putting Arc will come precisely shaped to your dimensions along with a CAD plot showing the variation from the standard arc.

Additional Theoretical Findings:

‘Straight-Back-Straight-Through’

The Putting Arc ... is an Ellipse