Pianotech

  • 1.  Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-20-2019 21:37
    This is the procedure I use.  The hammer flanges are not removed from the rail, but in order to give clearance enough to swing the hammer butts out of the way, the dampers are removed.  This takes about an hour longer than it would to replace the loop cord on flanges with butt plates, where the hammer butts can be removed.  Any suggestions would be appreciated.   Sorry for the lack of photos.

    1. Detach bridle straps
    2. Remove hammer rest rail
    3. Remove damper stop rail
    4. Number dampers
    5. Remove dampers.   Loosen but do not remove the screws from the flanges.  Grab 4 or 5 at a time and hang them from the outside edges of a suitable box with the lid removed.
    6. Rotate the action cradle so hammer flanges are facing up, hammers hanging down with enough angle to depress the whippens thus pushing the jacks out of the way.
    7. Apply acetone to the remnants of the old cord in the flange to soften it, about a dozen at a time (since the acetone evaporates rapidly), then scrape out the grooves in the hammer flange.  For this I use a small pick that has the end bent at 90 degrees, with the edge sharpened to a rounded chisel point.  Use adequate ventilation.  Use a suede brush to clean up and blow it out with air compressor.
    8. Cut 90 pieces of loop cord 50 mm in length.   I use .9 millimeter lift cord which I you can get from any mini blind supplier.  It has a similar appearance and diameter as the original polyester cord but is much stronger and more durable.  To make the tool for this take a 5/8" soft wood dowel and plane down 2 opposing sides until the circumference measures that length.  Drill a small hole at one end and fasten the cord with a nail head button.   Loop it around 90 times and then cut down the middle of one flattened side with a razor blade.  
    9. Glue in all cords on the left side only of the flange as you face it.   (I'm right handed.)   For this you will need a glue bottle with a small diameter opening.  I use titebond for this.  A very small drop of glue will suffice.  Ideally you don't want the glue to wick all the way up the channel to the top.   You will notice that old cords which are glued fast at the top always seem to break at this point as they wear due to the back and forth motion.  Allow the cords to dry thoroughly .
    10.  Orient the action cradle so hammers will stand in up position, canted just enough forward to hold them upright.
    11. Doing 4 or 5 at a time, apply a small dab of glue to the right hand channel.   Move the hammers up and glue in the cord.  This takes some dexterity, but you'll so get the hang of it when you've done a few.  I use small 6 " tweezers in left hand to maneuver the cord into position and the bent pick in the other, using the side of the pick to press the cord in the groove.  As long as no strain is put on the cord, you can wipe it into place.  When the glue is dry check then install springs.
    12.  Before reassembling, do some misc. housekeeping: Lube damper lift rod and spoons, jacks; tighten action screws.  Straighten any bent hammer butt springs.  If the bridle tape ends are delaminating, paint with PVC-E sizing and let dry before reinstalling.   When reinstalling dampers, be careful to counter-rotate until you hear the screw seat itself before tightening.  Aluminum rails have many advantages, but the ease with which you can strip screw holes is not one of them.  



  • 2.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-21-2019 07:09
    Cecil,

    Outstanding!  Thank you! You went above and beyond. I may have one of these jobs coming up.  Cool tip about the bridle strap ends. Never heard that before. 

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 3.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-21-2019 11:44
    Purchase a new set of flanges from Yamaha – not a third party vendor.
    Remove bridle straps
    Remove hammer/flange assembly from action rail.
    Remove flanges from hammer butt.
    Install new flanges – Yamaha flanges are sold with center pin installed
    Reinstall hammer/flange assembly -- Yamaha flanges require minimal spacing.
    Roger Gable





  • 4.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Posted 08-21-2019 19:17
    We do it the same way as Roger, but many do their own string replacements I know.  Either works, but replacing with new is a lot quicker!  We keep three or four new sets of Yamaha flanges in stock because it seems we are constantly doing that job in college practice rooms, etc.  However, if anyone would like us to save the old flanges, we certainly will and send them to you when we get a big baggie full!  We usually just give the old flanges to the customer or the music person at the school, just as a mechanic should show you the old parts that were replaced on your car's motor.

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    Ted Rohde
    Central Illinois
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  • 5.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-21-2019 19:38
    That too is a good idea.

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 6.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-21-2019 23:56
    The primary reason to replace the cords without installing new flanges is of course to avoid the labor in repinning and then aligning the hammers with strings.  Yes, the flanges come with a pin already fitted to the bushing, but that doesn't guarantee it'll fit the birdseye.   Another pitfall is the fact that in my experience there can be some difference, albeit slight, in the position of the flange centers in replacement flanges, even from Yamaha.  To imagine that all the millions of verticals that Yamaha ever made in all those different models in all those different assembly plants never varied so much as a millimeter in the position of the hammer flange center requires more faith and optimism than I can readily conjure up. Even a small difference there--a half a millimeter--requires some attention.   Any little thing, when you're talking 88 parts quickly adds up.  You replace a set of hammer flanges and you now own that instrument, whatever else crops up.

     I think in the end the difference in labor time between the two approaches is minimal--they're both going to take some extra time, but the repinning approach is fraught with more unknowns.  In a situation where the piano is used heavily, however, the wear on the hammer centers would be the deciding factor.  Ever technician's experience will inform his choices.  My customers tend to be mostly residential, not institutional, and the predominant cause for the repair is the flange cord rotting out, which it will do in the fullness of time regardless of how heavily it's played.

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    Cecil Snyder
    Torrance CA
    310-542-7108
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  • 7.  RE: Replacing spring loops on Yamahas with no butt plates on the hammer flange

    Registered Piano Technician
    Posted 08-22-2019 13:37
    So why though is it virtually Yamaha alone that has this problem? I have never seen it chronically on any other make.

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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