If you have ever struggled with arc stability while TIG welding, particularly in the lower range of amps that are suitable for the size tungsten, it likely can be attributed to improper grinding. Knowing how much point, and direction of grinding is key. In general, for all DC welding a sharp point is a good choice with a taper at least 2.5 times longer than the Tungsten is wide at lower amps. The same proportion should be used for higher amp range as well. However, to prevent issues with thorium spikes (with thoriated tungsten), and to reduce the risk of contaminating the weld, the point should by slightly snubbed, truncating the end, ever so slightly. This is good advice for DC welding with either an inverter or a transformer welder. However, for AC, the pure, green tipped tungsten that is used in a transformer will not usually be used sharp. Instead it will be balled from a flat tip, or a slightly ground tip. For an inverter, the same tungsten type and grinding can be used for AC as for DC, because of the capability to adjust the AC balance to a point that does not heat the tungsten to a molten ball. In these cases pure (green) tungsten will not be used. Whether it’s a transformer welder or an inverter, it is always critical to grind the point on a dedicated grinding wheel only used to dress the points on Tungsten to prevent contamination of the point. While grinding the tip should be ground along the length, and not radially. The fine striations that are made if radially ground around the circumference can create points of arc instability, making the arc hunt around the surface of the point.