When starting to use a grinding wheel, light pressure should be applied because:

Applying light pressure when starting to use a grinding wheel is crucial because too much force on a cold wheel can lead to catastrophic failure of the wheel. Grinding wheels are engineered to withstand significant operational stresses, but when they are cold, they are more vulnerable to cracking or breaking due to thermal shock or excessive force. Starting with light pressure allows the wheel to gradually acclimate to the task at hand, ensuring that it operates safely and effectively without risking damage or harm to the user.

Using light pressure also enables the operator to better control the grinding process and helps in achieving desired outcomes, such as proper material removal without overheating. This practice is important for maintaining both the integrity of the grinding wheel and the safety of the operator.