As your piano tuner Wilmington DE, Kenneth Keith Piano Services, I’d like to help answer one of the more common questions that I am asked by piano owners.
Due to normal wear, piano actions regularly get of of adjustment. In the piano trade, adjustments are called, “regulation.” So the term would be “out of regulation.” When a vertical piano action needs regulation, a common symptom is double-hitting, or “bobbling hammers.” This would manifest as the piano string being struck twice in rapid succession when a key is struck only once. This is often mistaken by piano owners as an indication that the piano needs tuning. In fact, the action is mechanically completely independent of piano tuning. A piano action can be removed, and the tuning is not disturbed at all. Also, the piano can be tuned, and the action regulation is not improved at all.
To eliminate bobbling hammers, the action must be at least partially regulated. Overall, there are 10 major adjustments to a piano action, and several minor alignments, as well. One or more of the major adjustments can cause bobbling hammers. The first step is to determine which of these is causing the problem, in order to make the most efficient correction. The most common cause in a vertical piano is a combination of “piano hammer blow” and “lost motion” being out of regulation. These are two of the ten major piano adjustments. When they get out of regulation due to wear, the action does not complete properly, causing bobbling. If those are not the cause, the next most common cause is shallow key dip due to compression of the balance rail punchings. It’s expensive to raise the key level, so the most cost-effective method of correction is to lower the punchings at the front of the piano key, so that the key travels farther.
If none of that corrects the problem, it may be that the backchecks are not catching the piano hammers, due to wear. If that does not correct the bobbling hammers, the last resort is to increase the let-off distance. It is the last resort, because increasing the let-off will make the piano action less sensitive, especially to soft piano playing. On worn piano actions, a piano technician occasionally is forced to make trade-offs in order to get an action to function.
If you have questions about your piano, any type of piano repairs or general piano maintenance, please let us know. Kenneth Keith Piano Services is your Delaware piano tuning service expert. We are happy to help. We also provided a full range of piano services in the areas of Philadelphia PA, Eastern Shore MD and Southern NJ.