What action should be taken to prevent cracks while dimpling magnesium or hard sheet metals?

Using hot dimpling equipment is effective in preventing cracks when working with magnesium or hard sheet metals because heating the metal increases its ductility. This improved ductility allows the metal to deform more easily during the dimpling process. When the metal is too cold, it can become brittle, making it more susceptible to cracking as it is shaped. Therefore, utilizing hot dimpling equipment helps in maintaining the structural integrity of the metal while ensuring a proper deformation without resulting in fractures.

In contrast, using lighter dimpling equipment might not provide the necessary force required to properly dimple harder metals, which could result in incomplete or ineffective dimpling. Standard hand tools may be insufficient for the task as they do not typically offer the precision and control needed for hard sheet metals. Cooling the metal before dimpling would be counterproductive as lower temperatures could increase brittleness and lead to cracks rather than prevent them. Hot dimpling thus presents the optimal technique for avoiding cracking in these materials.