Leveling Keys

Over time, the felt underneath the keys as well as the felt in the action becomes compressed.  Between this settling of the felt and dry rotting of paper and cardboard spacers (not to mention rodent infestations) the keys of many pianos tend to undulate up and down all the way across the length of the keyboard.  This can also be caused by damage to the keytops.  In this case, you will need to recover the keys.

The keys can be re-leveled by carefully adding or subtracting paper spacers underneath the felt punchings.  The tool of choice here is a 4 foot level (or any 4 foot straight-edge).  Make sure that it is true.  One way to do this is by laying on large piece of paper, cardboard, or wood and tracing the bottom edge of the level.  Flip the level over the line so the line is along the top edge of the level.  The line you drew should still match the edge perfectly.  If not, the level is not true and you should find something else to use.

Lay the level across the keys.  It should reach perfectly from the first key to the last.  Crouch down so that the tops of the keys are at eye level.  Generally, the first and last keys receive such little use, that they will already be at the ideal height.  Make sure the level is touching these two keys and not causing them to drop.

By repeatedly lifting and dropping one end of the level, you can find high spots in the keyboard.  Any key that drops from the weight of the level will need to either have paper spacers removed or have a thinner cloth punching installed.  These changes must be made underneath the keys at the balance rail, not at the front rail.

The level resting on the keys

The level slightly lifted at one end.

To find which keys are low, look for spaces between the tops of the keys and the bottom of the level.  Paper spacers must be added to the balance rail below these keys to bring them up to the level.  I get these spacers from either Schaff Piano Supply or Pianotek.  A general rule of thumb is that the spacers added should be about half the thickness of the gap between the key and level.  Move along the keyboard a leave an appropriately sized stack of spacers on top of each key that needs to be raised.

After you've made it through the whole keyboard, pull the level away.  Go through the keyboard one key at a time, pulling a key up, removing the cloth punching, placing the paper spacers on the pin, and replacing the cloth punching.  Reinstall the key and move onto the next one.  After you've gone through the keyboard place the level again and make a second pass.

After the key is removed

Cloth punching removed

Paper spacers added and cloth punching about to be replaced.

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Recovering Player Piano Reservoirs

This post is a continuation of the Milton Player Piano Series.

Inside the bottom of a player piano is a system of pedals, pumps, and reservoirs that creates the suction to operate the player mechanism.  The boards that make up one of the reservoirs in my player piano had started to delaminate and the rubberized fabric had pulled away from the board resulting in a serious air leak.  The best way to repair this is to cut and scrape the old fabric off, reglue the wood that delaminated, and recover the reservoir with new fabric.

Before cutting off the old fabric, measure the existing span of the reservoir and write this number down.  When recovering the reservoir later, I want it to end up with the same span as it originally had.

Measuring the original span of the reservoir

After writing down the span, cut away as much of the fabric as possible without cutting into the wood.  Be wary while doing this because the reservoirs contain very strong internal springs that can cause damage or injury if not handled carefully.

Excess fabric cut away

Internal reservoir spring

Remove the spring by squeezing it together and pulling it out toward the open end of the reservoir.  Once the spring is removed, the cloth hinge can also be cut and the two boards can be seperated.

Closeup of the delamination

Spread the lamination slightly by using a wedge, shim, screwdriver, etc. in order to make getting glue into the joint a bit easier.  Titebond 2 works just fine for this purpose.  Get enough glue in there to just barely squeeze out when clamped.  Wipe off the excess and allow the glue to dry.

Spreading glue

Glue drying while clamped

In order to remove the board that is still mounted to the trunk board, remove the six large screws from the front of the trunk

Six large screws to remove

The second board removed from the trunk

After both boards are free, use a sharpened paint scraper to remove the bulk of the rubberized fabric.  Then, clean the edges of the board by lightly planing them with a small block plane.  The goal is to only remove traces of cloth and glue.  Remove as little wood as possible.  Finally, go over all of the board edges with a sanding block with 80 grit paper.

Once the boards are cleaned they are ready to recovered with new rubberized cloth.  I acquire my cloth from Schaff Piano Supply.

This cloth should only be glued with hide glue (preferably hot hide glue) as it allows for an airtight bond while also being reversible for future repairs.  I've made up a small batch of hot hide glue in my glue pot for this repair.

Hot glue pot

Hide glue crystals

The first thing to do is to attach a new cloth hinge.  I use pedal webbing (also from Schaff) as the reservoir hinge.

Hinge Material

The reservoir needs both an internal and an external hinge.  Attach the internal hinge first by applying hot glue to the boards and laying the cloth hinge.  Keep the folded edge of the hinge flush with or slightly inside the edge of the boards.  Use a piece of wax paper to keep from gluing the boards together.  Clamp until the glue is dry.

Clamping the inside hinge

Move the clamps to the side edges of the boards and cut another piece of pedal webbing to size for the outside hinge.  Cover the edges of the boards in hot glue.  Do not use too much glue.  If any glue gets on the inside hinge, it will become stiff and won't function as well.

Push the hinge down onto the glue and tip the reservoir up on end, using it's own weight to clamp the new hinge.  After the glue has set, trim it with a new single-edge razor. 

Once both hinges have dried, cut another piece of pedal webbing to the length of the span distance that you measured before.  This piece will be glued across the open end of the reservoir and will work against the internal spring to hold the reservoir at the right span while it is recovered.

Internal spring reinstalled

The reservoir can now be recovered.  The most important part of this process is getting a glue seal that spans the full thickness of the board.  You will need to apply glue to the edge of the board, press the board against the cloth, and then pull the cloth back to see if you will have a good seal.  If not, add some more glue, press the board against the cloth, pull the cloth up, and check it again.

When gluing the cloth, it is important to get none of the glue inside of the reservoir.  To accomplish this, apply the glue to the edge of the boards, set them on top of the cloth and use a rocking motion on each board to squeeze the glue to the outside edge.

Glue one side first, then the open end, then the other side, and finally the hinge end.  Make sure you leave enough overlap on the hinge end for a good seal.

I like to trim the open end and the edges before gluing the hinge end.  Using a new single-edge razor blade, run it snugly along the edge of the board while pulling tightly on the loose end of the cut fabric.  You want this cut to be as clean as possible.

Glue applied to the hinge end

Let the glue dry for a day or so and then reinstall using the six large screws that were removed earlier.

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Review of Arthur Reblitz's "Player Piano - Servicing and Rebuliding"

Player Piano : Servicing and Rebuilding

Arthur Reblitz

1985 Vestal Press, Inc.

ISBN978-0-911572-40-7

This is the first book on Player Piano repair that I have purchased. I had previously purchased the second edition of Reblitz's “Piano Tuning, Servicing, and Rebuilding,” which I found to be very well written, well edited, and comprehensive enough for a book its size with its intended audience. Because of my positive experience with his other book, I had pretty high hopes for this one.

As this is my first book review, let me just start off by saying that the content of this book is fantastic. There is so much raw information acquired from decades of experience contained within this text. However, the organization of the content is an absolute disaster.

CONS

Unlike “Piano Tuning, Servicing, and Rebuilding,” the editing in “Player Piano” is horrible. Maybe the original edition of “Piano Tuning” was this bad too and was only fixed in the second edition, but if that is the case, Vestal Press should have re-edited them both at the same time 20 years ago. Before even getting into the main text, I flip to the Table of Contents which is nothing but vague chapter titles with page numbers and large useless blocks of text beneath them. Finding information on a specific aspect of the repair process is a real pain when the only reference you have is the start of a new chapter every 30-40 pages. The index is similarly scant. Only about 50% of the time does it lead me to the information I want.

The mostly useless table of contents

Once into the actual text, the photos are usually quite helpful, although occasionally there will be a photo that is unrelated to the text around it or a photo in which the parts indicated are indistinguishable from each other due to poor contrast. The book is also full of technical diagrams that appear to have been pulled from a different text, as they are covered in reference numbers, but the list of part names that the numbers reference is curiously absent.

Unable to distinguish parts in photos with poor contrast.

Diagrams that would be wonderfully specific if I knew what the numbers referred to.

The other thing about the layout of this book that makes no sense to me is the separation of Chapters 4 and 5. Chapter 4 gives a series of broad tasks to be completed for each repair in sequence. However, the specifics of how to perform each task is withheld until chapter 5. This leads to constant flipping back and forth between the chapters to figure out what to do from chapter 4 and how to do it somewhere in chapter 5. It seems as though the book was written for the rare person who can read straight through the whole thing, retain every bit of information, and then proceed to perform every repair they need to without ever having to look at the book again.

My final criticism is a simple one: the text is monotonous and too much information is crammed into a single page. In “Piano Tuning, Servicing, and Rebuilding,” the text is given plenty of space between lines and the monotony is broke up with bulleted lists, bolding, and clearly marked section titles. “Player Piano” has none of these things. It is just block of plain text after block of plain text with the occasional (barely noticeable) italicized technical term included.

A typical page from "Player Piano"

A typical page from "Piano Servicing, Tuning, and Rebuilding." Much easier to read and find what I'm looking for.

PROS

On the bright side of things, the content, as I said before, is wonderful. There are many pages of descriptions of the differences between many types of pneumatic covering material, glues and their strengths and weaknesses, types of cleaners and solvents, and even which species of wood is best for each application. The steps that walk you through each repair are very thorough and often give multiple methods for accomplishing the same goal, as well as many little tips and tricks that only come with years of experience and can make any player piano restoration easier.

One of the better images in "Player Piano." This image still has poor contrast, but the important parts of the image are easily distinguishable.

A good 90 pages of the book are dedicated to providing specific information about variations between different brands of player mechanisms. Although I don't expect to ever use most of this information, it is reassuring to know that if I ever run into some odd proprietary system, it is probably covered in this book. About 30 pages worth of those 90 pages is dedicated to different brands of reproducing piano and orchestrion actions for those who want to dive into repairing instruments even more complex than the standard player piano.

Included at the end of the text is a “Troubleshooting” section. I like the idea of having a consolidated troubleshooting section, but for some reason it misses many troubleshooting steps that are discussed earlier in the book while including some great ideas that are not mentioned in the previous corresponding chapters.

Again, the content of the book is incredibly expansive. Almost any question I have come up with is answered somewhere in this book. However, it often takes me longer to find the relevant information in the book than it takes to perform the repair.

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Re-gluing Damper Felts

The glue holding the bass damper felts on my Milton Player Piano had degraded to the point that the felts were falling off on their own.  They were still in good enough shape, so I decided to pull the remaining felts off and re-glue all of them.  

I start by holding the damper head firmly with one hand, while rotating the damper felt with the other until it comes free.  I work my way along until all of the old damper felts have been removed.

If I were re-gluing the treble damper felts, I would keep them in order, but for these bass felts it doesn't matter if they get mixed up.  Just keep the single-string dampers with the single-string notes and the doubles with the doubles.

To reattach the felts, I use Titebond Liquid Hide Glue.  Since the damper springs will provide the clamping action to hold the felts and damper heads together, I don't need the quick set that hot hide glue offers.  The liquid hide glue is much easier to work with and requires less set up time as well as less clean up.  

Some of the damper felts are not horizontally symettrical, so make sure that you keep them in the same orientation as they originally were.  The easiest way to do this is to keep the dirty side of the felt up and the clean side down.

Top side

Bottom side

Apply a small amount of glue to the back of the damper felt and then, using the strings as a guide, slide the damper down behind the corresponding damper head.  Allow the spring-loaded damper head to clamp the felt against the strings.

Try not to apply too much glue as it will squeeze out and fall onto other parts of the action where it doesn't belong.

Keep working along from left to right.  Going this direction will allow you more working room as well as better vision of the glue joint.

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Cracked Skid Board and More Stripped Screw Holes

This post is a continuation of the Milton Player Piano Series.

This time, I'll be repairing the skid board, which is the plank that makes up the bottom of the piano. The pedals, pedal rods, and blocks that the bellows mount to are all attached to the skid board.  

As you can see in the next few pictures, there are several large cracks running the length of the skid board.  This has caused the skid board to sag, which in turn prevents the pedals from working properly.  Also, most of the screw holes in the skid board are stripped out.  This prevents the pedal components from being firmly attached.

Before repairing the skid board, I remove all of the hardware that is attached to it.  There are a lot of pieces to keep track of here, so I number the bottom of each piece I remove, as well as draw a simple diagram to help with the reassembly later.

In order to make gluing and clamping the skid board easier, I use my Roll-Or-Kari Piano Moving Handtrucks to easily lift the piano an extra few inches off the ground.

The next step in repairing the cracks is to spread them slightly by tapping in a couple of wedges.  This will make it easier to get the glue all the way through.  Once the crack is opened up, I brush in some Titebond II, trying to get it all the way to the bottom of it along its whole length.

To clamp the skid board, I use these 3/4"  threaded pipe clamps along the underside of the piano.  After clamping, wipe off any excess glue with a damp rag.  Allow this to dry for 24 hours.

After the glue has dried, I attach these mending plates just for extra security against the crack re-opening in the future.  Any irregularities in the top of the skid board can also be smoothed out with a small block plane.

Now that the cracks have been repaired, I can move on to fixing the stripped screw holes.  The first thing to do here is to draw a large x through the center of each hole to be repaired.  This will assist in redrilling the holes in the exact same location later on.

After the X's have been drawn, I enlarge each hole with a 3/8" Forstner bit to about a centimeter deep.  I then proceed to glue a 3/8" plug into each hole, making sure to align the grain of the plug with the grain of the skid board.

This repair must be performed using plugs, not with dowel pins as the grain of a dowel pin runs the wrong direction.

Once the glue has dried on these plugs, the last steps are to extend the X's that I drew previously onto the plugs, make a dent precisely in the center with a sharpened punch, and predrill each hole with a bit that is the same size or slightly larger than the shaft of the corresponding screw.

After each plug has been predrilled, the pedals and pedal hardware can be reinstalled.

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