Here you see the bottom side view. It shows the hole that is ground at the back side using a Dremel and a small cylinderical stone or diamond burr. You can see the curvature of the bottom face and that it has been ground flush to the former cutting edge. Scott says "The bottom face of the dikes were ground on the flat side of the wheel using a slight radiusing motion as a slightly curved bottom works better than a flat one. By doing this you should automatically create the curved points on the tips of the blades."
The top view shows how the former cutting edge is changed by the bottom grinding to form the curved points at the front. This just happens as you grind a curve onto the bottom side. Notice too that the old hard-bevel cutting edge has been smoothed on the inside to make a nice ramping face.
Here they are in action! Scott says "The points are ground to a curve, this facilitates the action of pushing down on the fingerboard and pushing up the fret, it helps to keep you from having to pull up on the fret to get it out. This allows you to only have to squeeze the fret out." He just pushes the points of the pullers into the intersection of fret and fretboard at one end and squeezes a little bit, pushes some more and squeezes again, and progresses along the fret.
Half way across and you can see now what the hole at the back is for. The fret just passes out the back side of the pullers. The whole process took Scott about five seconds start to finish.
On to the next fret. You can see on the left where the first fret was pulled that very little of the fretboard chipped out. Only just little tiny bits right where the fret tangs came up. A fantastic tool, easy to make and inexpensive too. I think Scott should market them to StewMac and LMI.