[pianotech] sticky keys...thanks

[Tom Driscoll]

        Thanks John and Tom for your advice on the key and balance rail bushings and the
        hammer return spring thread, David. I think I will be in for a fun day.

        Ursula 

        ===========

        --- On Sun, 1/30/11, John Formsma <formsma at gmail.com> wrote:


          From: John Formsma <formsma at gmail.com>
          Date: Sunday, January 30, 2011, 3:25 PM


          I'd also agree that this is caused by the usual suspects.


          However, I'd alter the order slightly from what Tom wrote. First, you might want to first check the BR (and FR key bushings) before easing the balance hole. Sometimes a tight BR bushing can mimic a tight balance hole. (I recently looked at a piano with excessively eased balance holes. The real problem was in the BR bushings.)


          And, definitely check the balance holes and key bushings first before easing. Don't assume they all will need easing. I'm sure Tom does this -- but maybe just didn't think about mentioning that as part of the list.


          --
          JF



            John,
               Right you are. I didn't go into a lot of detail but my first test is to lift the key straight up and see if it will fall slowly on it's own weight. After the center bushing clears the top of the balance rail pin, if the balance hole  is really tight (Most of these grey markets are )the key will stay up.  I ease the balance hole just free enough that the key will fall .I set a depth guage on the CTF tool so I can assembly line the process and get the exact results on each key.  The key  will then usually hang up on the too tight center key bushing which will then be eased. My goal is to have the key slide down the pin without a freefall to rest with the least amount of play.
                Next test is to depress several adjacent keys at a time .With the sustain pedal depressed I hold them down firmly and release them all quickly. The slow ones are easy to identify and I ease the front rail bushings to create just the hint of side play that I prefer (judgement call) 
             In the past I have preped these greys (mostly U1,2,3's) for a dealer and in addition to the cord problem that David mentioned they all seem to have these "frozen keys"
            John, where you are spot on is that identifying the source is most important and of course don't ease if it's not necessary .Good post.
             And Ursula the cord problem that David mentioned is likely if this is a Yamaha. 
             Here is a pianotech archive link from some years back  for spring cord replacement .

            http://ptg.org/pipermail/pianotech.php/2002-May/108990.html

            Tom Driscoll

            P.S. In my first post I mentioned cleaning and lube on the keypins and that's where you will make sure none of the front rail pins have been turned 

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