Repair Spotlight: Hammer Rail Overhaul

The hammer rail is a vital action part which should receive attention in any upright piano restoration. The hammer rail functions to hold the hammer head / shanks at the proper distance from the strings (a measurement referred to as the "hammer blow.") The hammer rail is cushioned with a thick layer of felt (hammer rail felt) which silently catches the hammers / shanks upon release. The hammer rail on your piano needs attention at this point. The hammer rail felt is worn and needs replacing. In addition, while the rail is off the action for refelting, the surface of the rail itself could be polished (or refinished) for a more attractive appearance. Finally, the felt bushings in the holes that the rail pivots on (when the soft pedal is applied) could be replaced. The polishing is, obviously, more cosmetic in nature, while the refelting and rebushing influence the piano's performance.

The cause for the hammer rail cloth to deteriorate is either simple wear and tear, or the destructive action of moths and other felt-eating insects over the years. When the felt becomes worn, as in the photo above, the hammers are not caught at a consistent distance. Also, the action may be noisier, as the cushioning power of the felt is decreased. New hammer rail felt may be installed after the old felt is removed. New felt is essential if the piano is to be regulated, and if a quiet action is desired.

While the hammer rail is removed from the action for servicing, it is the ideal time to polish or refinish the surface of the rail. Old decals, such as those in the photo below, may usually be preserved to give the piano action back its original beauty.