Related Words: Hammer filing
Hammer shaping is the process of evenly removing felt from the surface of the hammer to re-define the strike point for optimal tone. The amount of felt removal depends on how worn the hammer is; hammers that have 12mm long string grooves will require more filing than hammers with only 6mm long string grooves.
Hammer filing strokes are done methodically, beginning at the base of the hammer and working up toward the strike point with long, even strokes in one direction:
Hammer filing is typically done with an abrasive paper; either sandpaper or microfinishing film. Different methods include strip filing and paddle filing.