Pianotech

  • 1.  Hammer bore geometry

    Registered Piano Technician
    Posted 19 hours ago

    I am hanging new hammer assemblies on a 1987 Yamaha C5. After carefully measuring the string height and hammer center heights, calculating the bore, everything looks like it should work out fine. But - the hammer shanks are buried in the rest cushions at typical hammer blow. The original hammers were bored shorter and so the shanks were resting comfortably above the cushions (well, would have been if the action had been regulated recently). I believe that Yamaha spec is for zero degree rake. So why can't I get this to work out? It won't regulate properly if can't get the shanks off the cushions. Has anyone else encountered this problem? 



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    Dave Conte, RPT

    Piano Technician in Residence
    The University of Tennessee
    College of Music
    Knoxville TN
    (817) 307-5656
    Owner: Rocky Top Piano
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  • 2.  RE: Hammer bore geometry

    Posted 8 hours ago
    I find Yamahas, you have to duplicate what was there. They had their reason, especially on a C5. 
    If you changed the original bore distance, that's the problem. 
    Dale Erwin mentioned problems like that on higher end Yamahas.





  • 3.  RE: Hammer bore geometry

    Registered Piano Technician
    Posted 7 hours ago
    The Yamaha spec may not have been 0 degree rake. Have you already bored the hammers?






  • 4.  RE: Hammer bore geometry

    Registered Piano Technician
    Posted 4 hours ago

    Dumb question:  Why did you not simply order new parts from Yamaha? (Repeat...dumb question 🤔) 

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 5.  RE: Hammer bore geometry

    Registered Piano Technician
    Posted an hour ago
    Not a dumb question. 
    I actually did, but this piano is an outlier with 23 bass notes. 
    The set I received was 26. I now regret not just modifying three hammers.
    But I returned them and ordered set from Brooks with Ronson Wurzen AA
    felt as the client thought the piano should have a better tone. 




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    Dave Conte, RPT, CCT
    Owner, Rocky Top Piano
    Knoxville, TN
    817-307-5656