How can you tell if the cam is flat?

To determine if a cam is flat, you can use a precision straightedge or a machinist's level to check for any deviations or warping across its surface. If the cam rocks or shows gaps between the straightedge and its surface, it indicates it may not be flat. Additionally, measuring the cam with a dial indicator can provide precise readings of any high or low spots that confirm its flatness. Finally, visual inspection under good lighting can help identify any noticeable irregularities.