Pianotech

  • 1.  '90's Baldwin L hammer bore distance

    Registered Piano Technician
    Posted 09-15-2014 13:13
    This message has been cross posted to the following Discussions: Pianotech and CAUT .
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    Good afternoon;

    Does anyone know off the top of their head what standard hammer bore distance should be for a Baldwin L from the early '90's? I grabbed an action from one of the practice rooms this morning to look it over to see what I'll do with the whole piano in a few weeks when I have room.  Somebody has replaced the hammers/shanks in '2010 a scribble on the shanks says.  It's just messed up and not regulatable.  I've got 2" bore distance and that doesn't sound right.  Potter's regulation book says 1-7/8th blow distance which is what it's set at, but the capstans are down so far there is 1/16" play in the keys before the reps move!  The key's are at proper height. The reps are really ugly. Action spread is 113mm. Flange to knuckle is 16.5mm

    It's no wonder this piano is the least signed up for in the practice rooms.  I think I just found a big project.

    Thanks
    Paul


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    Paul T. Williams RPT
    Director of Piano Services
    School of Music
    813 Assembly St
    University of South Carolina
    Columbia, SC 29208
    pwilliams@mozart.sc.edu
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  • 2.  RE: '90's Baldwin L hammer bore distance

    Registered Piano Technician
    Posted 09-15-2014 15:00

    Paul,
    Bore distance can be determined by examining the action and piano geometry. The given, is the fact the the hammer shank must be parallel to the string when the hammer strikes the string. With that understanding, the bore distance is determined by simply subtracting the height of the hammer flange bushing off the keybed from the distance between the keybed and string. This methodology can become skewed if the manufacturer incorporates a "rake" in the boring angle, but I've never encountered a rake in Baldwin grands. Also, this method can be cumbersome due to the high degree of accumulated error when measuring. I made a jig that most accurately measures bore distance when the bore distance number is unknown, but it is too complicated to describe how it works without a drawing. If you want to have me send you the diagram get in contact with me.
    Roger 
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    Roger Gable
    Gable Piano
    Everett WA
    425-252-5000
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    Original Message


  • 3.  RE: '90's Baldwin L hammer bore distance

    Posted 09-15-2014 17:35
    The info I have is 2.25" bass, 1.9" treble

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    Regards,

    Jon Page


  • 4.  RE: '90's Baldwin L hammer bore distance

    Registered Piano Technician
    Posted 09-16-2014 00:43
    Paul,

    I am not sure if I understand your statement, but
    bore distance and hammer blow are not interchangeable.

    As indicated above, Baldwins don't generally have a rake,
    nor are they designed to over-center, therefore the hammer
    shanks should be parallel to the strings, and so the bore
    can be determined by string height minus hammer center
    pin height. 2" does not sound that far off. If memory
    serves (and it sometimes looses my order and fails to serve
    or forgets at which table I am seated), the last model L that
    my hands rebuilt had about a 2 1/6" bass and 1 7/8" bore at
    the first tenor. You will certainly find that the string heights
    vary from one end of each section to the other, and over
    the entire scale. This is usually made up in regulation,
    but it's better if the hammers are bored to match the variations,
    thereby keeping the shanks in a straight line.

    If there is lost motion in the keys, and the capstans are
    turned way down - well, turn them up to make the blow,
    which is probably 1 3/4" in this model not 1 7/8", and the
    action might work fine. I would do that first to see what
    it's doing before swapping parts as a reference.

    Good luck.

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    Dave Conte
    Owner
    Fort Worth TX
    817-581-7321
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    Original Message


  • 5.  RE: '90's Baldwin L hammer bore distance

    Registered Piano Technician
    Posted 09-16-2014 08:07
    Yes I know bore and blow are not interchangeable, it's just where it is and the Potter book says in black and white 1-7/8th.  the hammers do have a rake for some reason.The previous tech had done a lot of goofs here that I'm discovering and will be doing a lot of do-overs of his later work before he quit..apparantly rather abruptly by what I've heard from folks here.  

    I can't figure out why these hammers were bored with a rake, who bored them, or even what kind of hammers they are (mahag with very thin purple felt core).The previous tech didn't leave any boring jigs, drill press, or any table top power equipment, so I doubt he bored them himself.  I went ahead with Fred's and all's basic bore distance measurements and it should be about 2" on average.

    I'm not going to go with Potter's book of 1-7/8 blow distance. That is where it is, but the hammers are resting on the rail and rail is set as low as it can go.  why the capstans have been turned down even lower is beyond me. 

    In the end, I think I'm going to dump the current hammers and start over from scratch and do it right. I'll probably also have to replace the shanks as the strike point will be different and shanks then will be too short.  This is one of the strangest set ups on a modern Baldwin I've seen. Don't get me started on the reps.

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    Paul T. Williams RPT
    Director of Piano Services
    School of Music
    813 Assembly St
    University of South Carolina
    Columbia, SC 29208
    pwilliams@mozart.sc.edu
    -------------------------------------------


    Original Message