What the Tuner Sees Inside Your Grand Piano

Posted: January 14, 2012 in Piano

Just a few pics for you.

I was repairing a pedal and thought to take a few pics so I can show you a few things.

With the action removed, I can inspect the player piano plungers. See the missing piece of felt? Here is what caused that. When the action is returned to the piano, the end of the key is brushing against the pieces of felt. Why? Because the plungers are too high. They can be jostled during a move. The clearance is 1/32 so the action should slide right in.

This is the bass section. Would it do any good to replace the felts without also adjusting the plungers? Yep! Got some work ahead of me on this one.

But while I have the action out, let’s look around a bit more.

These are the damper wires and damper lift rail.  Everything is fine here.

This is the mechanism for the sustenuto (middle) pedal. It rotates that steel transverse bar which enables pressed keys to be sustained while allowing others to be played w/o sustain.

This little critter is the rod tip that moves the action to the right when the left pedal is played. Called the “soft” pedal, it is really a “shift” pedal since it moves the entire action the width of one piano wire in the treble. Since the hammer only engages two wires in a unison, the volume is softer.

Hmm. This looks suspicious. This is the keybed, a very flat surface for the action, but made of somewhat softer wood. That round circle is hardwood. When the left pedal is pressed, the whole action assembly moves to the right.  The action rests on stainless steel buttons which slide on this hardwood area. That faint line extending from the button is actually an indentation in the wood. That should not be there. That is a symptom, but I am yet sure what is causing the symptom.

Here is a closer look. Ordinarily, if this piano had been prepped properly by the dealer. there would be traces of lubricate leaving a stain trail. As the action is removed from the piano, the excess lubricate will smear as the action is removed. No biggie, but in this case, there is a depression in the wood, and no stain. Also, there appears to be an application of wax on the hardwood button. I have not seen that before, so I am going to have to confer with my fellow tuners about this.

Not the most exciting photos on the web, but plenty to get excited about if your piano technician does not bother to inspect this area. I found three pencils in there too.

Things to do

1. Adjust plunger on player

2. Replace plunger felts.

3. Lubricate keybed buttons.

4. Tighten all screws

I may also lubricate the back end of the keys where they cantilever over the plungers so they can slide into place easier. Will think on that a bit.

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