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Advice for wobbly Yamaha G1?

  • 1.  Advice for wobbly Yamaha G1?

    Posted 05-23-2023 19:33
    UPDATE: Solved, so I'm editing the post to provide the solution for anyone who encounters this in the future. Thanks to the advice from members here I was able to use a standard open-ended 13/16" wrench to tighten the bolts used to hold the back and both front legs to the piano body and did not completely eliminate any sway but reduced it tremendously. There is still some motion when it's pushed hard from the side or played very enthusiastically, but it's far better and is solid enough to be safe and to be playable without the movement being a distraction. I only tightened the leg assemblies where they connect to the piano body, and did not make any adjustments to the joins in each leg. 

    Due to the curve of the leg there isn't room around the bolt for a socket to fit on, and when I measured I didn't have one big enough in any case (my largest is 15/16). I had tried using an adjustable wrench but because of the thickness of the wrench and the curve of the leg I was able to tighten one bolt a little when it was quite loose, but didn't have room to do as much as I needed before the wrench would be restricted from turning by the curve down to the leg. 

    ORIGINAL POST:
    We have a Yamaha G1 (70's) that has been great but it's starting to move (mostly side-to-side, but with some front-to-back). On the rear leg, one of the washers can spin a bit and though the front legs don't have that issue, I assume that the fact that it's wobbling means the legs are loosening up and need to be tightened. I have two questions that I need help with, though. 

    First, the bolts are square-headed, which seems to have been typical for Yamaha in that period:

    I don't have a square socket, so can't tighten them without gauging up the piano, which it appears some past owner did. Is my best bet to purchase a socket that will fit them and use the existing bolts or, given their age and apparent condition from the picture, see if I can loosen them off and then replace them with new bolts (likely with conventional heads)?

    Second, those bolts hold on the full leg assembly, but it appears that the assembly is made up of an upper portion that gets attached to the body of the piano and then another, longer leg part below that. I can see that the fit between those two parts is not as flush as it should be:

    I expect that this means that my problem may be in how the leg assembly is attached to the piano, or in how the upper and lower components of the leg assembly are attached to each other. If that's the case, is the best course of action just to remove each leg (with a support under that corner of the piano), tighten the mechanism that I assume must be accessible inside the leg once it's removed, and then replace the leg assembly?



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    Darryl Delamont
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  • 2.  RE: Advice for wobbly Yamaha G1?

    Member
    Posted 05-24-2023 00:06

    When was the piano moved to its current location ? You can tighten up the bolts buy purchasing a large open end wrench or an adjustable "monkey wrench" used fot plumbing fixtures. The threads on the bolt are likely metric and will be hard to match . The rear leg may need a washer and so may the side leg. The best way to do this is purchase a scissor motorcycle jack and use some 4 x 4 pressure treated posts cut into 2 foot sections. You can then safely jack up the piano enough to get the caster clear of the floor. Chances are adding some thin washers will take up the gap space  You may not even need to remove the leg , Before doing anything try tightening the bolts with a proper wrench- that may be all you need to do. You can make a shield out of thin aluminum roof flashing to protect the finish



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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    (843) 325-4357
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  • 3.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 16:45

    Thanks, James. The piano has been in place for about 8 years and we've only noticed this recently, so I don't expect that it is directly related to when it was moved (though it's always possible that it was not reassembled to spec and that's caused it to loosen up over time). Thanks for the insight regarding the threading: that certainly sounds like a road I don't want to go down if I can help it. 



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    Darryl Delamont
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  • 4.  RE: Advice for wobbly Yamaha G1?

    Registered Piano Technician
    Posted 05-24-2023 00:24

    If you have loose washers, make sure the screw hasn't bottomed out, which would prevent it from tightening completely.  Make sure that the proper sized screws were in the proper holes.  Often the lyre screws and leg screws are different lengths, the nose leg screws too.  If the longer ones are in the wrong holes, lots of damage can occur, the action can become jammed, etc.  Loose washers are a red flag, because nobody is going to just leave them loose. 
    Having said that, I have seen many legs where the upper plate and the leg are not joined very well, as you can see the gap in your photo.  I've tried filling the gap with epoxy or shims, etc., and not very successfully.  If the joint is loose, you'll need to disassemble it and reglue it, or somehow improve it.  Or just order new legs, which would be the best option. 
    Good luck.



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    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
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  • 5.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 16:56

    Thanks, Paul. I've tried to find schematics for these pianos, but it's challenging to find ones that are necessarily accurate to the time period when this one was made. All that I have seen, though, have the leg assembly as a single piece that's bolted on, so even though it's clearly made from more than one piece of wood, there's no further mechanism indicated to maintain the connection between the long, lower part of the leg and the upper part that widens out to join the piano body. I was aware that the bolts in the front legs are generally shorter, but they are seated where I would expect (so the amount the protrude below the piano is uniform front and back) so I believe that at least the bolts were used for the correct legs. 

    I'm hoping not to have to order new legs (not a very exciting upgrade despite, I would expect, coming in close to $1000 here in Canada), but I agree that if the piano is swaying and it's the separation between the upper and lower part of the legs that's causing it, it seems unlikely that a bit of glue is going to resolve the issue. While I'd rather not spend that money if I don't have to, I'd certainly rather spend it than have a potentially very dangerous surprise down the road. 



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    Darryl Delamont
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  • 6.  RE: Advice for wobbly Yamaha G1?

    Registered Piano Technician
    Posted 05-24-2023 01:53
    You can find a socket which fits the bolt. I think we used SAE not metric socket. Maybe 9/16" or 7/8" size.

    On most of these vintage 1970's pianos, often the rear legs were secured with lag screws, and the
    front legs used machine bolts. Also, the rear leg itself may be taller than the front legs. You'll know when you
    set the piano up and it's tilted. Don't ask me how I know... <g>.

    Beware, as a piano mover found out the hard way....do not use lag screw on front legs!
    It will go up into the cheek blocks and split them!!

    As to the leg separation, this is a failed glue joint. When you take the leg off, you'll see it's joined like the pillars on
    a pedal lyre. Likely a round dowel with a wedge driven into it to secure the lower tapered let with the 'head', or upper
    part of the leg. This will have to be taken apart and reglued.

    Both the bolts not being tight and the glue joint failure have attributed to the 'wobbly' piano.

    Michael





  • 7.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 17:20

    Thanks, Michael. Due to the curve of the leg there isn't room around the bolt for a socket to fit on, and when I measured I didn't have one big enough in any case (my largest is 15/16). I had tried using an adjustable wrench but because of the thickness of the wrench and the curve of the leg I was able to tighten one bolt a little when it was quite loose, but didn't have room to do as much as I needed. It turns out that a 13/16 open-ended wrench will work... it has a bit more play than I'd like but was manageable. I tightened the bolts holding the leg assemblies to the piano body and while that hasn't completely eliminated swaying when it's played enthusiastically, it's much better and at least at the point where it's safe and stable. Thankfully I won't need to explore the join between the upper and lower sections of the leg!



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    Darryl Delamont
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  • 8.  RE: Advice for wobbly Yamaha G1?

    Registered Piano Technician
    Posted 05-24-2023 08:56
    Hi, Darryl,

    I always carry an adjustable wrench. I never know when I’ll encounter a square nut or bolt. The top plate of the leg assembly is glued to the leg itself. If you remove the leg assembly you’ll see how that works.

    Bob Anderson, RPT
    Tucson, AZ




  • 9.  RE: Advice for wobbly Yamaha G1?

    Posted 05-25-2023 07:43

    A 12 point socket will fit a square headed bolt. I'm not sure what size socket it is, you'll have to try a socket to find out. 



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    Les Koltvedt
    Marietta GA
    lkpianos@gmail.com
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  • 10.  RE: Advice for wobbly Yamaha G1?

    Member
    Posted 05-26-2023 11:14
    Sometimes you can turn a socket extension around. Then you have a 3/8 and 1/2 inch square socket
    Use whatever you have to grab the end. 





  • 11.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 17:25

    That's a great idea - I hadn't thought of that!



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    Darryl Delamont
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  • 12.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 17:24

    Thanks, Les. In this case I wasn't able to fit a socket (it would run into the curve of the leg before getting any reasonable purchase on the bolt) but a 13/16" open-ended wrench worked to tighten the legs enough for them to be safe and functional again. 



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    Darryl Delamont
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  • 13.  RE: Advice for wobbly Yamaha G1?

    Posted 05-29-2023 17:22

    Thanks, Bob - my adjustable wrench was too thick, but a 13/16" open-ended wrench did the trick and that got it stable again, so thankfully the join between the upper and lower leg sections doesn't appear to be a major contributor to the issue. 



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    Darryl Delamont
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