Benefits of the Lindsay Graver Point Geometry
The five photographs below help illustrate the problem of heel drag with the traditional graver points, and show how the patented Uniform-Parallel point™ eliminates it. The five photographs were taken through a microscope, and are a series of cuts made on a steel plate. Click photos for more detail.
The first photo shows a complete shot of the plate. The two gravers that were used to make the cuts are lying on the plate, and are rotated so that the heels of the gravers can be seen.
The upper row of cuts was made using the patented relieving point, and the lower row of cuts were made with the traditional graver point. One of the points was installed in an AirGraver handpiece and a row of cuts was made with it. Then the other point was installed and the second row of cuts was made. The same power level (PSI level and piston stroke length) and hand motion were used to make the cuts for each point. Both points were made from Carbalt™ graver stock.
The two photographs below are close-ups of the traditional graver point cuts. Note the heel drag that is evident in the cut as the graver came around the corner. With the traditional point there is no clearance for the heel in the V furrow as it comes around the turn, and it drags on the outside of the arcs within the V furrow. Arrows in the photographs show where the heel first begins dragging. It can be seen that, as the traditional point continues around the corner, the heel hits with more interference and begins tearing. Click photos for more detail.
The two close-up photographs below show how the patented graver point cuts. Note how much cleaner these cuts are since the heel is not dragging through the cut. The heel drag is eliminated. The patented geometry works just as well for the fine cuts as it does heavier cuts, without having to alter the size of the primary heel. Click photos for more detail.
This is why various books and instructions advise engravers to hold their index finger on top of the point and push down to keep it in the cut when using a power assisted tool. This is necessary with the traditional graver, or it would be out of the cut and sliding across the work.
The downward pressure, however, also contributes to casting a bur on the edge of the cut. The downwards push is trying to force the tip to do something it refuses to do. This will help raise burs, and may require sanding the surface of the engraving when finished. After engraving, the surface should not need to be sanded or re-polished. If sanding is necessary, there is something wrong with the graver point. Sanding takes away the grays that were achieved while shading, and will lighten the overall engraving. It will also leave white streaks in the grays of the shading. The patented point solves this by making downward pressure unnecessary.
The uniform parallel geometry has a shorter heel because of the secondary relief facets, and allows the cutting edge to go through the metal cleanly and without drag. The point is therefore more efficient in cutting, and it takes less power than a traditional point to execute a cut of the same depth. The cuts in the sample plate illustrate this by the dramatic increased depth seen in the cuts made by the patented geometry, given the same amount of power and impact frequency as the traditional point cuts. In addition, since the point is cutting more easily, there is less force on it, and therefore the breaking of points is less likely.
The Lindsay Graver Sharpener helps grind this patented point
easily...click here to go to the Lindsay Sharpener page