Pianotech

  • 1.  Missing lyre bolts

    Member
    Posted 03-20-2021 22:14
    Hello all,

    My customer has a Hobart Cable grand piano made in China.  The movers lost the lyre bolts.  They are the same thread as the leg bolts but different lengths.  I measured the leg bolts and they are: M12 2.0  That is, they are 12.5mm thread diameter and a 2mm thread pitch. That does not match known fastener standards. A 12mm should have a 1.75 pitch and a 14mm has a 2mm pitch. The company making the piano is out of business as far as I could find. The question is, has anyone else encountered this problem and where could I find a replacement? They are the bolts that have the hex head. I have wondered if a custom 3D printed bolt would work if made of a hard plastic. Many thanks!

    Cary

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    Cary Thrift
    Marietta GA
    770-517-9871
    ------------------------------


  • 2.  RE: Missing lyre bolts

    Posted 03-21-2021 03:44
    Tap M14 *2 in the holes and use M14 bolts.

    Alexander Brusilovsky




  • 3.  RE: Missing lyre bolts

    Member
    Posted 03-21-2021 08:53
    Great idea!  Why didn't I think of that?

    Thanks! I'll try that and let you know how it turns out.






  • 4.  RE: Missing lyre bolts

    Registered Piano Technician
    Posted 03-21-2021 12:20
    Cary,
    No,no,no don't tap new threads over a different thread profile. You will get an extended cross threading that will fail after several on-and-off applications.
    These "strange" threads are unique to the Asian piano manufacturers. They're British Standard Whitworth threads. You can get replacement bolts from Samick.
    Roger

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    Roger Gable
    Gable Piano
    Everett WA
    425-252-5000
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  • 5.  RE: Missing lyre bolts

    Registered Piano Technician
    Posted 03-21-2021 12:24
    You might possibly find such bolts at Ace Hardware of one of the big box stores. I was surprised to see the selection of bolts at Ace the other day, not on the shelves or hanging in bags, but in the specialty fastener drawers. If you already looked there, then I'm wrong. Next time I'm there, I'm going to check it again.
    Paul McCloud
    San Diego



    Hello all,

    My customer has a Hobart Cable grand piano made in China. The movers lost the lyre bolts. They are the same thread as the leg bolts but different lengths. I measured the leg bolts and they are: M12 2.0 That is, they are 12.5mm thread diameter and a 2mm thread pitch. That does not match known fastener standards. A 12mm should have a 1.75 pitch and a 14mm has a 2mm pitch. The company making the piano is out of business as far as I could find. The question is, has anyone else encountered this problem and where could I find a replacement? They are the bolts that have the hex head. I have wondered if a custom 3D printed bolt would work if made of a hard plastic. Many thanks!

    Cary

    ------------------------------
    Cary Thrift
    Marietta GA
    770-517-9871





  • 6.  RE: Missing lyre bolts

    Posted 03-24-2021 11:14
    Drilling out old M12 tread with proper drill beat ( look at charts , function of material , type of tread and other minor things) will fully or almost fully clear the hole .Cross threading not an issue.

    Alexander Brusilovsky