Why should the grinding stone used for sharpening tungsten not be used for other metals?

• A. The grinding stone will heat up too quickly with other metals.
• B. Because of the hardness of tungsten and its brittleness, the grinding stone chips off small particles of the electrode. A course grinding stone will result in more tungsten breakage and a poorer finish. If the grinder is used for metals other than tungsten, particles may become trapped on the tungsten as it is ground. The metal particles will quickly break free when the arc is started resulting in contamination.
• C. It will produce a cleaner weld.
• D. It has no effect.

Answer: (B)

Tungsten is extremely hard but also brittle, so sharpening it requires care to avoid creating chips or cracks on the tip. A grinding wheel that’s too coarse will bite harder, causing more breakage and a rough, poorer finish. If the same grinding stone has been used on other metals, tiny particles from those metals can cling to or embed in the tungsten tip. When you strike an arc, those metal particles can come off and contaminate the weld, leading to inclusions or porosity and an unstable arc. Using a dedicated grinding stone for tungsten prevents cross-contamination and helps keep the electrode clean, giving a smooth, reliable arc.