Installing a larger diameter contact tip in a squeeze-type resistance spot welder will ____ of the spot weld.

• A. Decrease the diameter
• B. Weaken the weld
• C. Increase the diameter
• D. Have no effect

Answer: (C)

The amount of heat and the size of the weld in a squeeze-type resistance spot welder are tied to the contact area where current enters the metal. A larger diameter tip creates a bigger contact area, so the current is spread over a wider region. This distributes heating over a larger area, forming a bigger weld nugget and increasing the weld diameter. If you used a smaller tip, the weld would tend to be smaller because the heat is concentrated over a smaller area. The effect isn’t about strength alone; it’s about how the heat-affected zone scales with the contact area, assuming current and time are kept appropriate.