Pianotech

  • 1.  Bobbling Grand Tenor Hammers on a Soft Blow

    Registered Piano Technician
    Posted 05-18-2020 14:22
    I have often had the problem over the years, especially on Steinway grands, of bobbling tenor hammers on a soft pianissimo or piano blow. The hammer doesn't quite catch the back check and lightly double or triple strikes the string. I'm only talking about grands here, and generally only in the tenor area, although it can sometimes carry down into the bass below the break. I have played around with reducing the spring tension, and of course many variations on backcheck angles and alignments, as well as dip variations, but it doesn't generally help much. The one thing I haven't tried much is roughing up the hammer tails, but I'm concerned it would chew up the backcheck leather, and besides I don't want to have a checkered past. But I'll try that or anything else short of superglue and velcro...

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    Carl Radford, RPT

    Radford Piano Services, Inc. | Chicago, Illinois
    Ph: (773) 761-KEYS (5397) | Web: www.radfordpiano.com |
    Email: radfordpiano@gmail.com |
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  • 2.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Posted 05-18-2020 14:39
    Raise the hammer to create more after touch helps in many cases but if the rep spring tension is obviously too strong, reduce its tension

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    Petrus Janssen
    Peachtree City GA
    678-416-8055
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  • 3.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Posted 05-18-2020 15:16
    Quick and dirty...lower drop a tad. If you are doing a nice tight regulation on an older action, the existing checking system will be challenged, and checking will be horrible. Lowering drop takes the rep lever and spring out of the picture, and check is less challenged. This, like I said, is the quick and dirty fix.  You may have noticed that older unregulated actions often have great checking. The reason is,that drop has usually sunk way, way low. Low drop takes the spring out of the picture.  So, although bringing drop up, is essential to really nice touch, the further drop is brought up, the more the spring and rep lever will keep the tail from checking. This means the checking system has to be in good condition and fine regulation, to survive nice high drop. 

    Lowering drop a tad, also keeps the double strike from happening, even if check still is not happening. The hammer may bobble silently, but it won't double strike.

    Lowering letoff to 2mm will allow you to have letoff and drop in a good synchronous relationship, so if you want to retain the nice "second keyboard" bump of synchronicity, lower both letoff and drop a tad.  

    At conventions teachers will promote tight regulation specs. However, if you try to apply tight specs to a tired action, you'll leave a trail of poorly checking actions, unless you dealt with the checking geometry and/or busckskin. Both of the true fixes to the checks take a fair amount of time to accomplish.


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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 4.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Registered Piano Technician
    Posted 05-18-2020 22:03
    Increasing the drop seemed to do the trick. Thanks for the tip. Perhaps my tolerances were a little too tight in that area. And for the record, I wasn't referring to this so much as a problem in older, worn out actions, but rather usually with new or recent replacement actions.

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    Carl Radford, RPT

    Radford Piano Services, Inc. | Chicago, Illinois
    Ph: (773) 761-KEYS (5397) | Web: www.radfordpiano.com |
    Email: radfordpiano@gmail.com |
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  • 5.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Posted 05-18-2020 23:11
    One of the reasons this might be happening, in factory actions, is that factory &S hammers are generic bores. This means, given S&S plates which bow across the width of the piano, string height in certain areas will be slightly out of spec for the generically bores hammers. Unless the check heights are installed uneven  to accommodate this condition , which they usually are not, the height of the checks will be incorrect in parts of the scale. Incorrect check head height means checking will not be optimal.  Same for any generically bored replacement hammers on an action rebuild.

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 6.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Registered Piano Technician
    Posted 05-19-2020 11:31
    It depends on the reason why.  

    1. Inadequate aftertouch
      1. Key dip too shallow
      2. Blow distance too great
      3. Jack/knuckle alignment not set properly (jack too far back)
    2. Let-off and/or drop too close
    3. Rep spring too tight and/or action centers too loose.
    4. Poor checking
      1. Due to wear or age of the backcheck leather. Sometimes a ledge has been cut into the leather (see below)
      2. Improperly angled backcheck or bad relationship between backcheck angle and tail arc
    So all those things should be checked.  The problem could be one or a combination of things.  Changing any one of them might solve the problem but it may not be the correct solution.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 7.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Posted 05-19-2020 14:07
    When the hammer is held in the Drop position, the height of the b/c should be level with or 2 mm below the tail. The b/c should have a angle of 68~72 ° (I prefer 72). The arc of the tail is usually between 2.5"~3". Make sure there is not a square edge to the tail to impact the b/c. I prefer a sweeping catch rather than an impact to check-in.

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    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
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  • 8.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Registered Piano Technician
    Posted 05-20-2020 18:36
    I think Jon Page has clued in to the problem. I have the same experience with the tenor hammers bobbling. It often is either a hammer tail too short, and/or the back check height is too low. Plus the points mentioned about back check angle.

    Joe Wiencek




  • 9.  RE: Bobbling Grand Tenor Hammers on a Soft Blow

    Posted 05-20-2020 20:13
    What is the length of the tail? 1 1/16" (27 mm) is what I prefer. When I order hammers, I get them from Ronsen because I request a longer molding to accommodate an appropriate tail length, I add 30 mm to the longest bore I will be drilling to allow for trimming. A stock set will have shortened tails if a tapered bore is done.

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    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
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