I’ve been reading a little on preparing the tungstens for TIG welding (GTAW). The tungsten in your TIG welder is a critical component and the correct grinding will affect the ease of use and the quality of your weld.
Most tungstens have small quantities added chemicals such as thorium to improve their properties such as reducing burn away or improving the starting of an arc. They are colour coded to help you identify them. A red thoriated tungsten is most common for welding mild steel.
The shape of your tungsten will affect the arc and penetration of the weld. Typically the tungsten is ground to a truncated cone for best all round performance. A sharp angle would produce a long thin point which would have good arc stability and a wide penetration pattern. A short stubby point would give a narrow arc but it may be less stable. A sharp point on the end may break off and contaminate the weld so should only be used for thin materials with lower currents.
You should grind with the tungsten straight onto the grinding wheel not on the side or perpendicular. This is to avoid concentric rings on the tip that would promote arc instability. It is also a good idea to use a separate grinding wheel for your tungsten than for your other workshop tools. This stops other metals contaminating your tungsten which could in turn contaminate the weld.
Reference thanks to Miller Welding