Replacing or Restoring a Piano’s PinblockThe pinblock (sometimes also called a wrestplank) inside of a ‘standard’ grand piano must withstand approximately 40,000 pounds of tension from the numerous strings. As a pinblock ages under this consistent tension, the holes in which the tuning pins are driven become worn and enlarged. This causes the pins to become loose and compromises the stability of the tuning. The sheets of laminated wood can separate and the glue joints loosen.
The piano won’t stay in tune and of course, this affects the quality of the sound and the overall playing experience. Restoring or replacing the pinblock becomes necessary and the piano technicians at Chupp’s Piano Service begin a process that is skillful and precise. There are many times when the original pinblock can be reconditioned allowing it to serve well for many more years. However when the highest stability is required, it is best to replace the original pinblock with a new one that is custom crafted for the specific piano.
Removing the Original Pinblock
Before the piano is dissembled for restoration, the bearing is measured to check if the plate is at the correct height. (The pinblock plays a large role in the height of the plate and the amount of down bearing.) Once the bearing is checked, the strings and plate are removed and a large number of very precise measurements of the original pinblock’s position are taken. These measurements are very important as they are used to position the new pinblock upon installation.
Next the old pinblock is cut out and removed from the piano. (Dowels and glue joints hold the original pin block in place.) The original pinblock is saved to be used as a template for the new block. When replacing the pinblock, having the new block custom fit to the plate in the piano is essential. When completed correctly, the new pinblock will fit just as well – or better than the original.
Crafting a New Pinblock
The new pinblock is cut from a sheet of laminated hard rock maple or beech that is slightly thicker than the original pin block. The multiple laminations allow for increased strength and for the grain of the wood to grip the pin from various angles. The new piece is cut down to the approximate size of the original pin block leaving some extra wood to allow for the fitting process. The new pinblock is then hand fitted to the contours of the plate and is planed down to the correct thickness. Once again, using the original pinblock as a template is key.
Once the new pin block is fit to the plate with no voids or imperfections, the bolt holes are drilled and the new pinblock is bolted to the plate. The location of each tuning pin hole is marked. The new pinblock is then unbolted from the plate and the approximately 230 tuning pin holes (the number is different for the various models) are drilled in the precise location they were marked so they will line up with the holes in the plate. The measurements that were taken of the original pinblock are then used to install the new pinblock in the same position as the original. The new custom fitted pinblock is doweled and glued into place.
With the new custom fitted pinblock installed in the piano the plate is then installed and bolted into place on top of the block and the new strings and tuning pins are installed. A new custom fitted pinblock will ensure the highest stability of tuning for many years to come. There are some instances when saving the original pinblock is possible. When this is a viable option we utilize our various time tested methods to ensure a tight tuning pin fit and an overall stable pinblock.
Installing a new pinblock requires the block to be crafted to exacting tolerances and with an eye to detail. One pinblock issue that we have run into over the years is a bad fit between the pinblock and the cast iron plate. With all of the pressure placed on these components, it is obvious that a tight and correct fit between them is key to the stability of the instrument. Unfortunately we have discovered more than several pianos that were shipped from factories with an almost non-existent fit between these two pieces. Click here to read our in depth article on the process we utilize to repair this critical issue without replacing a fairly new block. You can rest assured that when we do replace a piano’s pinblock, our blocks are custom fit and precisely drilled and installed.
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