Accurate filing is an essential skill for final shaping and removing imperfections or fire scale prior to finishing a piece of work.
When filing larger pieces of metal in a vice, the correct position must be maintained to ensure accurate filing. The vice should be at the same height as the elbow; this will help to keep both the file and the forearms level. The body should be kept as still as possible, the arms should pivot at the shoulders. For fine jewellery work the work should be held much higher than this. The comparatively high worktop of a jeweller's bench allows close observation when filing.
The dominant hand should hold the file handle in the palm, with the thumb along the top and the index finger pointing along the side. Maintaining this grip will help to keep the file level. The tip of the file should be gripped with the other hand.
For coarse filing, the tip of the file should be grasped under the ball of the thumb, with all fingers underneath. For finer control, the tip can be help between the thumb and forefinger. For the kind of light filing work that is common in jewellery making, the file can be held in one hand. In this case, the forefinger should be on top of the file, pointing forward along the file. This will allow full control at the wrist, the majority of the pressure coming from the forefinger.
Pressure should be applied evenly on the forward stroke; gradually transferring pressure from the back to the front hand. Pressure should not be exerted on the backstroke, as this will dull the file teeth.
When filing sheet metal or smaller pieces of work, is can be easier to maintain a flat surface if the filing is done diagonally across the work. If this is done then the angle should be switched from the left to the right after every few strokes.
Progress should be checked regularly, straight edges can be easily verified by holding a steel ruler against the work, any imperfections will show light though the gap.
