Key Bushings: Keybed Inspection

Posted: March 9, 2013 in Piano, Piano Regulation, Regulation

I am replacing the bushings on my piano keys. The piano is a 1928 Lester Grand. Today I am checking the level of the keybed. As I view the wood of the keybed, there are many clues that can help me learn the history of the piano, what has happened to it over the years of its life, and the impact the keyframe has had upon the wood. I have placed photos on this page, and very large photos on another site, so you can see what I am looking at here in the shop. Below, the keyframe (containing the action and the keys) have been removed. I am sitting on the bench looking into the piano. The wood you see is called the keybed.

Photo A: Keybed Left

keybed.left.small

D is the edge of a water mark. So is E. F and G are indentations in the wood. C is an area that has several watermarks. B (upper left) is the word area where the back of the keyframe meets the keybed. A (far left) is a discoloration in the hardwood frame of the keybed.

A close up of areas F and G is shown below.

keybed.center.front.small

Interesting? What would have caused these indentations? They are not equidistant, so I’ll assume they were made by single blows to the keybed by an instrument. They are all similar depth, so I’ll assume the same force was used in each blow. I also notice a darker color to the interior of the marks which matches the color on the very front edge, and towards the upper portion of the photo. If  a light coat of varnish was applied to the keybed, it was applied after the indentations were made. If true, then the indentations were made prior to the varnishing step, which would be a final step in the construction of the keybed. Therefore, the tool which was used to make the indentation would be among the tools that are used prior to the completion of the keybed. the edge of a chisel would make a mark like this. Also the claws of a hammer.  Why were these marks made though? How odd!

Photo B – Keybed right

keybed.right.small

At H (bottom left) the indentations continue and form a pretty straight line. They are not as deep. F is a stain with a dark residue. D is a drop of something resembling the varnish found on the piano and at the very right edge of the keybed. C is a stain which conforms to the shape of a rectangle. A is a watermark. B is where the keybed meets the keyframe. At C then, a contained rested on the piano for a short period of time. The bottom of the container was either wet with a liquid prior to being placed on the keybed, or it contained a liquid which caused condensation on the container which leaked onto the keybed, or the container itself has a small leak, or for some other reason. Area C is under the pinblock, which would not be an ideal area to place a container that was being used to complete a step in the construction of the piano. it may not have been a container – it may have been a piece of cardboard or paper.  It may have been placed there to get it out of the way temporarily, or as a rest for the varnish brush. There is enough wear to the wood on the right side that I remain curious to know if at least the frame of the keybed was varnished.

I will inspect the keys and pinblock to see if there are any watermarks which line up with the watermarks on the keybed. This will tell me more about how the watermarks were made.

Photo C: Keybed center

keybed.center.small

Again, you can see the long line of indentations at B toward the bottom of the photo. Area A (top center) is where the keybed meets the keyframe.  The remainder of the marks were shown in the other photos.

I determined that the keybed is level by using a level. A good flashlight was used to project light under the edge of the level to see if any light was able to move under the bottom of the level. The surface of the keybed is smooth to the touch.

It is tempting to light sand the surface to make it more attractive to the eye. However, sanding will not increase its functionality, but it will alter the appearance and make it more difficult to identify any existing marks in the wood – which may later be useful in identifying clues that may not seem important at this time. Sanding the keybed only eliminates evidence that may later prove to be helpful troubleshooting a future problem. The keybed is level, so there is no reason to alter its surface. I can proceed with the rebushing of the keys.

The Point of the Exercise

The piano technician views your piano differently than you do. Every single mark on your piano, inside or out, is potentially evidence that might be helpful in determining why a problem exists, what can be done to repair the problem, how the problem originated, how the piano has been cared for over the years, and what conditions have had an impact on the piano.

I will post links to the larger photos after I built the HTML page necessary to display them. Then I will post links here.

Until then, enjoy your day.

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Comments
  1. The condition of the keybed tells a story. Each water mark, stain and indentation may represent a chapter in the history of the instrument. I’m fascinated by the process, thanks for sharing, I look forward to more as you progress through the piano.
    How did you come by this 1928 Lester Grand? What are you playing on while you refurbish it?

    • Kent Moore says:

      I may set up the Rhodes. I hope the lack of an instrument motivates me to finish the action in reasonable time. I bought the Lester several years ago as a rebuild project. As I am able, I invest money in the project. It is a killer piano!