I have a baby grand piano and the middle D key has been getting seemingly 'clogged/stiff', when I press it once after first sitting down it usually works fine but then will become stiff and not sound, feeling as if there is a piece of felt blocking the key.

Upon taking the front lid off, I noticed that the jack is occasionally falling further than normal after releasing the key. I also notice that the jack is a bit further to the right than other keys, if that means anything. Sometimes lifting the key up a bit will make the jack go to where it should be but sometimes it won't.

The best solution I have come up with so far is putting something between the key and the jack, which stops it from falling too far but the problem still occurs when I press the key repeatedly quickly without fully releasing it. If I repeatedly press it slowly, there is less stiffness at first but the sound becomes weaker gradually to the point where there is no contact between the hammer and strings.

My current research suggests issues relating to the guide and balance pins but they don't seem to be the problem, the key appears to be better aligned than most of the others.

What is causing this and how do I fix it?

  • Is there a reason you aren't having a piano tuner come over to fix this? Normally I'd want a pro to fix my beloved and expensive musical instruments rather than root around myself unless I really know what I'm doing. And your instrument could cost more than a car, so the expense of a pro seems justified rather than risking ruining anything permanently. Sep 3, 2015 at 9:56
  • I would without a doubt have a pro come over, mind you it seems a lot of the piano tuners I know can only do exactly that, tune pianos, and are pretty useless at fixing them. Still, if it involves taking something apart I would much rather pay someone to do it safely.
    – FaceySmile
    Sep 3, 2015 at 11:49
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    Only reason I haven't so far is because the last person I asked to failed to even address the issue, so I suspect it may be out of the scope of the average piano tuner.
    – FaceySmile
    Sep 3, 2015 at 11:56
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    If you have anyone you like who works on your piano, ask them for a referral. If you have any friends who have grand pianos, ask them. Try the store where you bought the piano or any high-end piano stores in your area. I'm all about DIY but not when it comes to the brakes on my car, refretting my expensive guitars, or any other highly-skilled work that could damage something very valuable. Sep 3, 2015 at 13:19

1 Answer 1


have you tried to dismount the mechanism to look at the axes and there felt bushings ? in particular the jack's one ?

the felt bushings are the parts of a piano mechanism that get damaged the sooner.

  • I'm not totally sure what you mean, can you elaborate with reference to this diagram? (amadeuspiano.net/grand_action.jpg, that's where I'm getting all my technical terms from). Also, is dismounting the mechanism something I should leave to a pro?
    – FaceySmile
    Sep 3, 2015 at 11:54
  • I thought you knew how to dismount the whole mechanism (all the 88 mechanisms in one block). Try it first on a cheap upright piano. The jack rotates on a small metal axis, which is stranded by some felt into the jack's wood (the contact felt/metal also makes the movement smooth, there is no lubricant in pianos). often, the small metal axis is just displaced, but when replacing it you must be careful with the small felt joints.
    – reuns
    Sep 3, 2015 at 12:45
  • I see what you mean, with a lack of any cheap piano's to play with I'll get someone to come in and show me how to do it properly but I think I can tell what's causing the problem. Thanks.
    – FaceySmile
    Sep 3, 2015 at 21:05
  • @reuns It's an easy 5-minute job to take the action out of an upright piano, but taking the action out of a grand is a completely different ballgame. There is a classic "gotcha" which will break off a couple of hammers if you do it wrong. (And making that mistake once in their lives is almost a "rite of passage" for piano techs!) And the bad news is that since the action of a grand is sandwiched between the strings and the bed of the keyboard, you can't do anything much in the way of repairs without removing the action completely.
    – user19146
    Sep 3, 2015 at 23:42

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