[pianotech] Sluggish key diagnosis

[Paul McCloud]

Hi, Michael:
    Next time you want to remove the bushings, you might try soaking a sliver of hammer felt in a mixture of wallpaper remover/water and insert in the bushing hole.  It seems that you may have "cooked" the key with too much steam.  You just need to wet the bushing cloth, and most often it will just fall off (assuming hide glue was used).  
    As far as how tight it should be, be sure you're using the correct cauls for the size pin.  Sometimes the two pins are different sizes.  For the front bushing, there should be a very small amount of play side to side.  Maybe a few thousandths.  If you're using the correct cauls, and everything is done right, you shouldn't have to ease the keys very much.  You might visit Michael Morvan's website and see how he does key bushings.  (Somebody give the URL here).  The key should slide down onto the pin of it's own weight, but not like you heaved it off a cliff.  It shouldn't "chuck" forward/backward on the pin.  If you lift the wippen with one hand, the key should be free to move easily up and down without much friction.  If you feel resistance, something is wrong.  Either bushing could be too tight.  The front bushing affects the key movement the most, so a little too tight there will cause more problems than the balance rail bushing.  The balance rail hole is sometimes too tall, which could bind on the pin.  See recent discussion about this on the list in the last week, with pics of a jig for correcting this problem.
    Hope this helps.
    Paul McCloud
    San Diego
    


----- Original Message ----- 
From: Michael Staples 
To: pianotech at ptg.org
Sent: 08/06/2010 8:31:51 AM 
Subject: [pianotech] Sluggish key diagnosis


I'm rebushing the keys of a Baldwin Hamilton studio and would like to get the list's help with this:

Starting with the first 10 keys as a group, I steamed out the old bushings (using a pressure cooker without a jiggler on top), used Spurlock's .146 in mortise sizing cauls overnight and rebushed with 1.20 mm bushing cloth and hide glue, placing the cloth 3/16" into the mortises.  The steaming seemed to swell the balance rail holes and my bushings seemed tight when I placed the keys back in the piano.

Can you tell me what indicates a sluggish key to you and what steps do you take to isolate where the problem is (front rail pin bushing, balance rail pin bushing, balance rail pin hole, etc)

Thank you,

Michael Staples
PTG Associate Member
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