Filing Best Practices
Do not try to file hardened steel with a (hardened steel) file; you will quickly ruin the file. Also diamond-embedded files should not be used on soft materials, including many softer steels, as this will cause the diamonds to be torn out.
Clean out any bits of file metal with a stiff wire brush.
Chalk/oil/lard the file: rub a small amount of lard/oil into the teeth of the file to:
If using Lard or Oil, don't forget if you need to do work that requires the surface to be clean of it.
Clamp the work in the vice. It should stick out far enough that you don't rub the file on the hardened steel jaws of the vice, but if the work extends too far, it will vibrate or chatter, making the work take longer and the finish worse.
HEAVY CROSS FILING: for course work, grab the handle of the file handle with one hand and place the palm of the other hand on the end of the file. Point the file away from you, press down firmly enough that the file digs in and cuts the metal while making long, slow strokes away from your body. Remove downward pressure on the return stroke so you don't dull the file.
LIGHT CROSS FILING: for detail work, grab the handle of the file with the dominant hand and place the fingers of the other hand on the end of the file. Orienting the file so that it points away from you, press down firmly (so that the file digs in and cuts the metal) and make long, slow strokes away from your body, removing downward pressure on the return stroke to prevent dulling the file.