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Re-sizing Birds Eyes

  • 1.  Re-sizing Birds Eyes

    Posted 11-03-2025 11:44
      |   view attached

    Looking for tips on resizing birds eyes. I am refurbishing the action of a 150 year old piano that has seen its fair share of playing and repairs.  Many hammers have been previously re-pinned with very large center pins yet they are extremely loose (again).  I am re-bushing the flanges. (Photo shows underlever flanges in progress; the hammer flanges need the same treatment)

    How can I reduce the hole in the birds eye so that I can re-pin with reasonably sized pins?



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    Jurgen Goering
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  • 2.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 11:48
    I would suggest CA glue. Insert a 49, add glue to both sides, let it penetrate and harden, then pin 50. (or whatever size the bushings are). 







  • 3.  RE: Re-sizing Birds Eyes

    Posted 11-03-2025 12:08

    You might be better off doing it Wims way or just replace the the hammer shanks. Filling the hole with wood and re-drilling for a perfect perpendicular hole requires a lot of skill and time. You need a jig to hold the hammershank in the correct position, and the precision of an end mill to pull it off, along with correct drill speed and technique because the small drill bit that can easily wander.

    -chris



    ------------------------------
    On the page, it looked....nothing.
    The beginning, simple, almost comic.
    Just a pulse - bassoons, basset horns, like a rusty squeezebox. And then suddenly, high above it..an oboe, hanging there unwavering, until a clarinet sweetened it into a phrase of such delight.
    This was no composition by a performing monkey!!

    865-986-7720 (text only please)
    ------------------------------

    Original Message


  • 4.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 12:33

    Don't forget to use mold-release on the pins.  If you try to reduce the size more than a size or two, make sure the pin is sitting straight in the hole.



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    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
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    Original Message


  • 5.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 13:03

    I have typically glue-sized the holes using well-watered-down wood glue.  I have let the water evaporate before inserting a pin.  



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    Floyd Gadd RPT
    Regina SK
    (306) 502-9103
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    Original Message


  • 6.  RE: Re-sizing Birds Eyes

    Posted 11-03-2025 16:42
      |   view attached

    Before more people suggest using new parts, please view the attached sketch of the action in question. These parts went out of production around 1880. This is an Ed. Westermayer patent action, one of several which he invented.

    Pete: any suggestions for "making sure the pin is sitting straight in the hole"? I have to go down considerably in pin size. For this, I tend to think that wood glue might be more flexible/compressible than a bead of CA glue, which gets glass hard. Thoughts?



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    Jurgen Goering
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    Attachment(s)

    pdf
    Westermayer Action Sketch.pdf   524 KB 1 version
    Original Message


  • 7.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 17:23
    I think the thick viscosity CA glue won’t get as hard as the medium or thin. It also sets up much faster. But the wood glue will work, too.

    Wim.
    Sent from my iPhone


    Original Message


  • 8.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 17:48

    Whether I am correct or not, I understand glue-sizing to be a process where the moisture expands the compressed wood in the direction of its original specification, and the presence of a bit of wood glue in the mix works to stabilize the newly expanded material.  I typically aim at a 50-50 glue and water ratio, but I probably end up with more water than glue.  If I'm glue-sizing key balance holes, I use Elmer's Glue-All, which I understand to not dry as hard as other optionsthat could tend toward noisiness.  Otherwise I use regular wood glue. I've had good results with birds' eyes.



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    Floyd Gadd RPT
    Regina SK
    (306) 502-9103
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    Original Message


  • 9.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 19:41

    You could drill and dowel holes,  the re-drill.



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    Parker Leigh RPT
    Winchester VA
    (540) 722-3865
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  • 10.  RE: Re-sizing Birds Eyes

    Posted 11-03-2025 20:57

    Parker Leigh: "You could drill and dowel holes,  the re-drill."
    Have you done this with success? Please share directions and photos of your jigs and your drill bits.
    I am hoping to not have to undertake this, but if I do i would certainly not use a dowel, which has the incorrect grain direction. I would  use a plug.  

    But I am open to real life, tried and true experiences.  I have enough of my own speculations so please spare me those...



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    Jurgen Goering
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    Original Message


  • 11.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-04-2025 08:44

    Reply to post # 10:  Glue sizing is the best option in most situations.  Drilling, doweling and repinning requires a small mill, custom cutters and setups. I am assuming that if you are doing this job for a customer and are charging time and materials. If not,  then this would be an experiment.



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    Parker Leigh RPT
    Winchester VA
    (540) 722-3865
    ------------------------------

    Original Message


  • 12.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-03-2025 23:03
    Hi Jurgen,

    I have successfully glue sized birds-eyes.  50/50 water and Titebond is what I used, I ran a "wet" piano wire through the birds-eye hole to immerse with the glue size to be sure I've thoroughly soaked the hole, and waited 24 hours before repinning.  Back when Steinway vertical butts were unavailable this was an indispensable approach, which I have felt was applicable to any original parts birds-eye restoration.

    I would suggest you might experiment with cold hide glue size and  especially thinned hot hide glue too.  

    The idea, of course, is to slightly expand the wood as well as to reinforce that wood with the gluesize.  I was able to avoid overly-large centerpin sizes this way, and use rebushed flanges.

    Bill




    Original Message


  • 13.  RE: Re-sizing Birds Eyes

    Posted 11-04-2025 00:35

    I see no birds eye in the sketch presented. If its the screw clamp system those are easy to fix.



    ------------------------------
    Chernobieff Piano Restorations
    chrisppff@gmail.com
    Youtube@chernobieffpiano
    865-986-7720 (text only please)
    ------------------------------

    Original Message


  • 14.  RE: Re-sizing Birds Eyes

    Posted 11-04-2025 11:15
      |   view attached

    Regarding the drill bits, you can't use a standard bit because of the small diameter. So you would need to get custom bits. Since i work on many pianos that parts are no longer available. I tooled up a long time ago to manufacture my own parts. In the photo is a birds eye making tool along with the specialty bits needed.

    -chris



    ------------------------------
    Chernobieff Piano Restorations
    chrisppff@gmail.com
    Youtube@chernobieffpiano
    865-986-7720 (text only please)
    ------------------------------

    Original Message


  • 15.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-04-2025 18:42

    Travers Tool is a good source for miniature end mills and drill bits. Still a big job and a last resort.



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    Parker Leigh RPT
    Winchester VA
    (540) 722-3865
    ------------------------------

    Original Message


  • 16.  RE: Re-sizing Birds Eyes

    Registered Piano Technician
    Posted 11-04-2025 13:38
    I too have had success with gluesizing the bird’s eye. I have sometimes sprayed the bird’s eye on both sides with rubbing alcohol, hoping the alcohol would draw more water into the wood. I have used a size or two smaller pin than I intended to install as a caul. I have also sized without the caul successfully. I don’t think a mold release is necessary, the force from the pinning tool to break the thinned glue is enough to release any hold.

    I would certainly try wood glue and water before CA, and absolutely before plugging and drilling.

    Joe Wiencek
    NYC