Over the years, working as your piano tuner Wilmington DE, Kenneth Keith Piano Services, I have seen numerous pianos that have one or more piano hammers that strike twice when the key is played only once. Many piano owners mistakenly believe that the piano needs tuning, when in fact the mechanical action of the piano needs attention. In our three previous blog articles, I explained a lot of the background information about double-striking or “bobbling” piano hammers, and I explained the most common causes: “lost motion,” improper hammer blow distance, and decreased key travel. This post is a continuation detailing the correction if decreased piano key travel is the cause of the problem.
To review, a piano action is an “escapement” mechanism. That is, the portion of the action that propels the hammers toward the string must “escape” from its initial position, so that the piano hammer may rebound from the piano string, and thereby strike the string only once. If there is insufficient key travel, then the piano action may not complete its escape, leading the hammer mechanism to strike it and rebound toward the string a second time. This would result in a bobbling hammer.
As a piano ages, the various felt pieces that support the piano keys get compressed, resulting in less key travel than is needed. The proper adjustment is to raise the level of the keys back up to the original specification. The trouble with this is that it is very labor-intensive to level the keys again, so the adjustment is relatively expensive. For a high quality piano, this is appropriate.
For the average home piano, the owner may not wish to spend the money for raising the key level. The inexpensive short-cut is to increase the key travel by lowering the felt punchings at the front of the key. This is called, “increasing the key dip.” It can result in a correction of most of the problem with only a fraction of the expense. Your Wilmington DE piano technician, Kenneth Keith Piano Services, can test and recommend which of these corrections is appropriate for your piano.
This concludes our series of posts regarding bobbling hammers. Our next post will cover a new subject.
Along with our Delaware locations, we provide piano services Eastern Shore MD, Southern NJ and in the city of Philadelphia. If you have questions about the care of your piano, please give us a call or email us. We are your piano tuning Wilmington DE experts.