Graver Point
The Patented Lindsay Uniform-Parallel Point is a V shaped graver point with relieved heels that works with any width V graver point, from a narrow V to a wide V. The most noticeable feature of the geometry is parallel width heels with two long secondary relief facets on the bottom of the point.
Note: Traditional 110, 120 and 130 degree gravers do exist. They are described in the prior art section of the patent. However, the patented point with the relieving cutting edge is different and will cut with less drag. The point can be utilized on narrow points under 90 degrees as well as the wider points.
The Uniform-Parallel Point is similar to having two flat graver points joined together to form a V. While engraving, lean it to one side or the other and it will cut wide like a flat point. This makes the point versatile and allows a person to vary the width of the cut from thin to thick easily.
The engraving to the right would have been difficult if not impossible to execute well without this point. Being able to vary the width of the cut using one point to create fine banknote lines and wide lines gives the artist the ability to express himself easily.
One pre-sharpened Carbalt graver with this point is included with each customer's first purchase of an AirGraver handpiece. The sharpening system easily grinds this point, as well.
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.
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.
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.
Additional Benefits
The heel relieving graver can go deeper into the metal than a traditional graver point using the same power level. The heel on the traditional graver point is actually giving more resistance as it is driven through the metal. This is especially evident around corners like those shown in the sample plate. While making a cut, the traditional graver tends to come up out of the metal, and it is therefore necessary to push straight down on the point itself to hold and keep it in the cut around the corner.
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.