What technique should be avoided when using emery cloth on a shaft?

Using emery cloth on a shaft is a task that requires careful handling to avoid damaging the surface being worked on. Employing a spiral motion is not advisable because it can create uneven wear on the shaft and lead to an undesired surface finish. When working with emery cloth, the goal is typically to achieve a smooth and consistent finish, and the use of a spiral motion can introduce imperfections that compromise this goal.

In contrast, perpendicular motion usually helps to maintain even pressure across the surface, while using gentle pressure can prevent excessive material removal and damage. Similarly, using short strokes allows for more controlled sanding, ensuring a more uniform finish. Therefore, avoiding spiral motion when using emery cloth is crucial for achieving the intended results on the shaft.