Which type of material would most likely require special handling to avoid warping during drilling?

Stainless steel is particularly susceptible to warping during drilling due to its unique physical properties. It has a higher strength and a greater tendency to work harden compared to other materials. When drilling, especially if the drill bit generates excessive heat or if the speed and feed rates are not properly controlled, the localized heating can lead to thermal expansion, which can contribute to warping.

Additionally, stainless steel can be more difficult to cut than softer metals, requiring appropriate tooling and handling techniques to minimize stresses that can lead to distortion. This might involve using cooler cutting speeds or employing coolant to manage the temperature, thereby reducing the risk of warping effects during machining operations.

In contrast, while mild steel, aluminum alloy, and copper can all have their own challenges during machining, they generally exhibit more forgiving behaviors regarding warping compared to stainless steel. Mild steel and aluminum are often more ductile, allowing them to endure some deformations without significant structural changes. Copper, similarly, is relatively malleable, which helps reduce stress concentrations during machining.