Player Piano, Music, Rolls, Service, Repair, Care, Dampers Regulating Upright Dampers by Craig Brougher One of the most important as well as difficult tasks of piano regulation are the dampers. This article explains how to adjust them on an upright, particularly after replacing them. Before replacing dampers in an upright, you should measure their depth.
Some modern replacements are too thick.
What you are going to have when you get through will be a damper line that lifts evenly from the strings with the damper lift rail and the key. They will operate exactly like a finely adjusted grand. Once you get all the damper heads cut off the blocks, lay the action horizontally with the damper blocks facing you on the bench and soak the remaining glue off, scraping, warming, whatever you need to do to clean them up. Then do not install your new dampers quite yet. Replace the action first and align the damper head blocks a little better with the strings.