What is the recommended method of filing soft metals like lead or aluminum?

The recommended method of filing soft metals like lead or aluminum is to use only the forward stroke. This technique is effective because soft metals tend to be malleable, and applying pressure on both strokes or only on the backward stroke can lead to the material tearing or becoming distorted. The forward stroke allows for a more controlled and consistent cutting action, reducing the risk of deforming the soft metal.

Using both strokes or applying pressure inappropriately could produce an uneven finish and might damage the file itself over time. Filing without applying pressure would be inefficient, as it would not remove material effectively. Therefore, focusing on a controlled forward stroke is crucial for achieving a smooth surface and maintaining the integrity of both the metal being filed and the file being used.