Damper System Installation Practice

It all starts from nightmares that the damper system was put in wrong, or the parts were broken in pieces, and there were dust in the package where worms crawled everywhere eating and chewing happy.

​We try our best to replicate the backaction exactly as the original unless where were flaws in the old system. Every screw hole has to be marked and drilled precisely and spaced evenly. Usually music, podcast, or any distractions are banned for the day. The assembly process takes about 8 hours. This is a Renner Backaction. The assembly training material can be found on the Renner USA website :
ttps://rennerusa.com/training-manuals/

After the backaction is installed in the piano, it is time to install dampers. The damper heads will look better visually if they are evenly spaced. Often times the strings are not spaced evenly due to plate casting, agraff spacing, bridge pin patterns, and more. One need to juggle between visual effect and functions. A damper functions the best when it is centered above the strings of that note.

Usually, for the same note, the damper guide rail hole and the damper wire post hole are not on the same vertical line. The damper wire need to be bent at two locations to create a "Z" shape, and the top and the bottom parts vertical. A little too much bending can cause the wire to bind on the guide rail hole bushing. It takes patience and many breaks away from the piano.

After all dampers are in place, the damper felts are glued on. The supply houses provide enough felt for uni-cord, bi-cord, and tri-cords notes for the specific make of a piano, usually with extra pieces for technicians to make mistakes. To help the glue to set, sand bags, rice bags, or anything heavy can be placed on top of the damper heads. For now, the damper installation takes 2 whole days. I tried to go faster only to find myself making all sorts of mistakes. Accuracy first.

By the end of the whole process, one can temporarily take a deep breath. The timing and movement of the dampers will be further adjusted. To be continued.