Rebuilding a 40 to 150 year old piano is a major undertaking. Restoration may take up to 300 hours. There is so much information that could be discussed about this process that, in my opinion, it would fill a thousand page book. My goal in this section is to hopefully give you a better understanding of what it takes to get a piano back to its original glory while at the same time, not to overwhelm you with so much information that it will make your head spin.
I prefer to break the rebuild down into three major parts: the Belly, Action and Case. Many pianos are not in need of restoration to all three parts. However, in this page we will go through all three processes.
Part 1: The Belly
The belly is the heart of the piano and consists of the sound board, pin block, bridges, tuning pins, strings and plate. The most common reason the belly needs restoration is because a usually small portion of the roughly 250 tuning pins are unable to stay in place and hold the tension of the string which helps to keep the piano in tune. Tuning pins are made of steel, roughly ¼” in diameter and in most pianos 2 3/8” long. Every string in the piano is coiled around a tuning pin and driven partially into a pin block. The piano is tuned by the turning of these pins. Each string has about 200 lbs. of tension pulling on the pin. At some point in the pianos life these pins will stop being able to hold this tension, they will slip and the piano will go out of tune. Unfortunately, this means it’s now time for some restoration. To fix this problem a new pin block is needed. The pin block is a roughly 1 ½ inches thick, multi-plied, usually quarter-sawn hard maple board and is supported by the rim, piano structure and a large cast iron plate. The tension created by the sum of all the strings is an incredible amount; a rough estimate being 50,000 pounds. Replacing the pin block will require pulling the plate out of the piano, replacing the tuning pins and strings as well. Moving on to the rest of the belly. A string will stretch from the tuning pin, go over a bridge that is connected to the soundboard and finally to a small steel hitch pin that’s driven into the plate. The tone is carried from a vibrating string through the bridge to the soundboard. The soundboard is meant to amplify this tone. The sound board should have a slight crown to it. The soundboard has ribs glued to one side of it to help maintain this crown. It is also glued to the rim of the piano. The connections from the strings, to the bridge, to the sound board, to the ribs, to the rim should all be tight in order to produce a rich and clear tone. Almost always, when we do belly restoration, there are loose connections that need attention. Sometimes a new sound board is needed to accomplish this and sometimes repairing the old board is sufficient to get a high quality tone. Besides fixing loose tuning pins the other major benefit from belly restoration is the solidifying of all these connections.
Here are some photos of some of the steps taken rebuilding the belly of 2 recent Steinways we’ve worked on:
The new block is cut out of a raw piece of pin block material. Once cut out, it has to be meticulously fitted to the underside of the plate, the belly rail and rim of the piano. Then it is drilled for the new tuning pins and finally glued to the rim of the piano.
After the block is done, the sound board and plate are repaired, sanded and refinished. The plate also gets the model and serial number re-stamped.
The raised letters are all highlighted just like the original. All of the hardware is cleaned and polished. New stringing cloth is added and we’re ready to drop the plate back into the piano.
Time for new strings.
Sometimes a new sound board is needed. Here a Steinway model D is getting fitted for ribs.
Using a soundboard press and about 200 go-bars for clamps, the ribs are glued to the back of the new soundboard panel. Many steps are taken to ensure the new board has optimal crown and that all glue joints are very tight.
The ribs then need to be shaped. All the work is done by hand. Next the bridge is glued back to its original location on the new board.
More rib work. Matching the shape and dimensions of the old ribs is very important. The picture to the right shows the crown. This will help the tone resonate with a long clean sustain.
Just like the original, 1/4” hardwood dowels run through each rib to into the bridge glued to the top side of the board.
Now we can start the bridge work. First the bridge must be surfaced to the proper height. This is called “setting the down bearing”. The strings must be pushing down slightly and also evenly on the bridge but not so much as it takes away too much of the crown. Once the down bearing is set, a pattern taken from the original bridge cap is laid over the new cap and using punches the locations of the original bridge pins are marked. The holes are then drilled out.
One of the most favorite jobs in the shop is notching out a bridge cap. This is all done by hand with a very sharp specialized chisel. The black surface is a dry graphite lubricant to help the strings slide easily over the bridge. Finally about 500 bridge pins are hammered into place. The bridge pins are driven in at a slant and will hold the strings down to the bridge. That pin is critical to transferring the tone from string to the sound board. Many times we will find older pianos that have loose bridge pins. It’s not hard to imagine the negative affect loose bridge pins will have on the tone of a piano.
The final results on this piano were amazing. The original board was flat, had no crown, the majority of bridge pins were loose as were the soundboard to rib connections. The new board had plenty of crown with good even down bearing and all the connections were very tight. With all the positive changes, the tone was incredible with a powerful long sustain.
Part 2: The Action
After the belly is complete, it’s time to move onto the action. A typical action rebuild includes replacing virtually every moving piece (excluding the keys themselves), all felts, key-tops, refinishing the sharps and damper heads. However, not every action restoration is the same. Many times ivory key-tops are savable; some of the various felts are still in good condition and sometimes major action parts can also be reused without compromising the tone and touch.
The main factors that influence the condition of the action parts and action felts are the amount the piano is used and also it’s age. A piano that is played several hours a day will undoubtedly wear at a faster rate than a piano being played for a short period only once per week. Typically, the lifespan of an action is 30 to 40 years; however, that will vary from piano to piano depending on usage and also the quality and maintenance of the parts and action. In many cases a piano can still be used and if regulated properly, can play and sound pretty good even after 40 or 50 years of age. However at some point if the desire is to get the playability and tone it back to its very best, the older parts and felts just won’t be capable of accomplishing that outcome no matter how much work is put into reviving them.
Our belief when restoring an action is to adhere to the manufacture’s intentions and not try and reinvent the wheel. When completed, the action should play evenly and smoothly from top to bottom. The tone should be rich and even.
Once all of the parts and different action felts have been replaced, the process of making it play like it was when new and with a beautiful tone, begins. We’ve counted 29 steps that we take to make this happen. For the people that may be interested the steps are:
- Lubricating friction points on key frame and capstans
- Action frame seating to the key bed
- Key easing
- Key spacing
- Key squaring
- Setting key height
- Setting key travel
- Hammer shaping
- Hammer traveling
- Hammer squaring
- Hammer to string alignment
- Action alignment to hammers
- Set let off
- Set drop
- Set repetition spring adjustment
- Set jack position
- Set repetition lever height
- Set hammer blow distance
- Set back checking
- Damper alignment
- Damper timing
- Set damper up-stop rail
- Set pedal timing
- Sostenuto adjustment
- Action shift adjustment
- Rough tuning
- Hammer to string mating
- Fine tuning
The above list highlights each significant step. There are many little things that are also done. In the end, the result is a piano that once again plays and sounds like new.
Part 3: Case – Finishing
The finish on a piano is unlike the finish on a typical piece of furniture. Piano finishes usually consist of varnish, lacquer, urethane or polyester. The newer higher end American pianos (like Steinway or Mason and Hamlin) comprise of several coats of a high build lacquer. The older pianos that have a crackled look, are generally a varnish. The other thing that is unique about piano finishes is the fact that they are smooth and do not sink into the grain of the veneer they are sprayed on. Satin finishes like the type you will see on most pianos, are hand rubbed. That is, very fine and straight scratches that follow the direction of the wood grain are put into the finish using different abrasives. The high polish pianos are actually first sanded smooth with very fine grit sand paper and then polished with a buffing wheel. Either way, to accomplish the same finish that you see on a new, good quality piano, it will take roughly 100 hours hand work.
- Strip off the old finish
- Roughly sand
- Repair and re-veneer where needed
- Finer sanding
- Spray seal coat
- Grain filler
- Spray 4 coats of lacquer
- Spray 4 more coats of lacquer
- Let dry for a minimum of 2 weeks
- Sand until by hand smooth with 400 grit sandpaper
- Sand by hand with 600 grit sandpaper
- Rubbed out with 4/0 steel wool and wool wax
- Polish hardware or nickel hardware re-plated
- Seal hardware
- Assemble piano