Facts on Piano Keys

Did you know that piano keys used to come in a set of 85 but since the late 1800s, 88 keys became the norm. And practically all pianos made today have plastic key coverings for both the naturals (white keys) and the sharps (black keys). Formerly the naturals (white keys) were of ivory, the importation of which is now prohibited because it requires the killing of elephants for their tusks. It has not been used to make the naturals (white keys) since about the 1950’s. Now piano manufacturer uses plastic for the key tops (piano keys) as plastic are very durable, require much less maintenance and are always available.

Sharps (black keys) used to be made of ebony wood; the plastic sharps used today may be shiny or of a slightly dulled appearance. Professional pianist would recommend the dulled sharps (black keys) which are often standard on the better pianos because fingers seem to slip off the shiny ones more easily.

Till today, most pianist still very much preferred Ivory keys because it absorbs sweat from the fingers and doesn’t get slippery like plastic does. It is also said to have a “warmer” or “softer” feel to it. Therefore, there are several piano manufacturers have developed synthetic materials that mimic the properties of ivory which referred to as “Ivorine”.

How to differential between a real Ivory and Ivorines?
Just because the keys are yellowed or discolored doesn’t mean they are ivory. Ivory key tops are always made from three pieces per key, two pieces on the key top and one on the key front. There is a distinct grain, much like the grain of wood, and sometimes it can only be seen under good lighting.

Following are some pictures on key tops

A set of refurbished Ivory key tops and Genuine Ebony sharps. Note one sharp has been buffed to a high finish, the other was finished with a satin rub.

Ebony Sharp Keys showing front and bottom part

These key tops have a grained look which simulates ivory and is an excellent replacement for ivory.

This is set of black and white plastic key tops with fronts attached, the white keys look much brighter and cleaner than ivory whilst the black are hard wearing and have a classy matt finish which compliments the white perfectly.

Touchweight

You may have noticed that some pianos are easier to play; others require more effort. If you are doing a lot of practicing, or playing, or are attempting to become proficient on the piano, it is important to understand some basic issues about touchweight.

The forces required to maintain key movement, collectively called “touchweigh”. These forces include downweight (the maximum amount of weight that will cause a piano key to go down at the front) and upweight (the maximum amount of weight a key will lift at the front upon being released).

On different pianos it might vary from 45 grams to 70 grams (26 grams make up one ounce). Differences in leverage, mass of various parts, and frictional resistance yield piano actions that play very differently.

But don’t think that a lighter touch is always better. In fact, most advanced musicians like to feel a touch that is anywhere from 52 to 58 grams. If a piano is too light, will not enable you to build up finger strength properly and there’s no feedback from the piano back to the player. And if the touch is too heavy, will lead to fatigue, make your practicing less rewarding, arms and fingers tire easily and may ultimately lead to serious muscle injuries, further sensitive control is gone.

If the touchweight on your piano is not what it should be, or what you desire, touchweight adjustments can be performed to make it the way you want.

What causes Sticky Keys

Sticking keys is a common problem with pianos, and can happen to any of them. A sticky key is one where the note does not respond quite as it should e.g. it can be played once.

There are many causes of sticky keys
Excess moisture often causes keys and felt bushings to swell and react sluggishly or even stick. It is very important that excess moisture and moisture fluctuations be minimized as much as possible.

Common symptoms / causes and cures (upright pianos)

The note is played and the key stays down:

• The key itself is physically stuck down
• The front of the key is fouling on the slip rail
• Slip rails is warped – shave some off or reposition it
• The front bushings are binding on the key pin
• The key pin is rusty – clean or replace
• The bushings need lubricating and / or easing

The key is free but the action has not returned:
The note is played and the key returns but when struck again the note does not sound

1. The hammer has not returned

• The tape has broken – replace
• The hammer flange is stiff – lubricate or repin
• The butt spring is broken – replace
• combination of the above

2. The jack has not returned under the hammer butt

• The jack (spiral spring) is broken – replace
• The jack flange is stiff lubricate / repin
• The key capstan is adjusted too high – adjust down

3. The whippen has not returned to its correct position

• The wippen flange requires lubriaction / repinning
• The front of the wippen is fouling (the frame sometimes) – shave some off (!)
• The damper spoon is corroded / caught against back of damper bottom (underdamper only) – replace damper box cloth and / or clean / replace spoon

If in doubt – consult your technician

If the pianos have keys that stick, are they Worthless?
Saying a piano that has a sticking key is “worthless” is like saying your house is worthless if a door sticks when the humidity is up a little. Would you tear down a house because a door was sticking? Of course not. If you tossed out every piano that had a sticky key, you’d have to toss out every piano ever built.

Sticking and Sluggish Keys

Piano keys can stick down or become sluggish for a seemingly infinite array of reasons including, but certainly not limited to; foreign objects caught between the keys, jammed or broken interior action parts, warped keys rubbing together, broken keys, and a whole variety of causes associated with moisture. Cross section of a piano key Unfortunately, it may not be readily apparent whether the cause of a sticking key is in the piano action or the key itself. To determine this it is necessary to have access to the action, usually calling for the service of a professional tuner.

However, a common cause of keys that stick down (or fail to sound on a repeated stroke) is moisture in the key bushings. As can be seen in the cross section drawing, the key is guided in its up and down motion by two metal pins extending up from the keybed; a balance pin in the center of the key (at the balance point where the key rocks on a falcrum), and a thicker guide pin near the front of the key which serves to keep the key from wobbling sideways. Both pins extend through channels in the key which are lined with a thin felt bushing cloth (shown in red in the drawings).

Although the balance pin rarely causes much problem, the guide pin can be quite troublesome, especially in very humid conditions. Even a small amount of moisture trapped in the bushing can swell the felt and cause it to grip the pin too tightly. The result can be a key that either sticks down, or fails to return on the upstroke enough to allow the action parts to get back into position for a repeat stroke. This is a frequent condition on new pianos since the bushings are a very tight fit to begin with, in order to allow for eventual wear. To properly remedy this condition a piano technician removes the key and uses a special tool to compress the felt.

However, sometimes the pin can be freed by slightly compressing the bushing by hand. Grab the key at the front and move it laterally back and forth (as indicated by the arrows in the following drawing) to press the pin against the felt. Naturally you cannot see the pin without removing cabinet parts, but if you attempt to move the key sideways you will feel the resistance of the guide pin. Do not apply great pressure, but slowly and firmly move the key back and forth several times and press the pin against the felt to compress it. On white keys you may use moderate pressure since the wood in the key is quite thick, but remember the point is to compress the felt bushing, not the key wood. Also be very cautious when applying this technique to the black keys; the wood is much thinner in these keys and too much pressure could risk cracking the wood. The object here is to just compress the felt enough to free the guide pin. If moving the key laterally three or four times doesn’t do the trick, forget it. The problem is probably elsewhere.

If there is too much swelling of the felt, or the problem is in the action, you will be obliged to call a piano tuner and have the key removed and the bushing compressed. If sticking keys are a consistent problem with your piano, a dehumidifer installed inside the piano may solve the problem. Check with your piano tuner for info on dehumidifing systems.