Notes that stick only when damper pedal is down.

[dlux]

I'm working on a 1974 stage 88 . It had 75 stuck notes when I got it. A few notes  still stick but only when the sustain pedal is depressed. The Vintage Vibe guys said " You probably have swollen key bushings" I have worked and worked on the key bushings with a key bushing tool. I have lubricated the pins etc. Now the odd thing is when the harp is flipped up they don't stick. The second you put the Harp in playing position they start to stick again. The hammers aren't getting stuck on the tines  or  between them. Any suggestions would be appreciated . Thanks- Dlux

[David Aubke]

When the harp is up, the dampers are allowed to rise up as well because the tines aren't holding them down. When the dampers rise up, they pull more firmly on the bridle straps which in turn cause the hammers to press down more firmly on the keys which helps them return to their upright position. When the damper pedal is depressed, the dampers are lowered thereby reducing their pull on the hammers removing some of the keys' motivation for returning upright.

The weight of the hammers alone should be enough to convince the keys to rest on the keybed felt in back. If they're not, it's either the key bushings (either front or balance) or something preventing the hammers from falling freely back onto the pedestal.

[sean]

Are the keys getting caught on the front lip of the piano case?  If the tolex is loose and bulging out, it can catch a key.

Also look for keys that are rubbing up against their neighbors.  Fine sandpaper can wear down the contact areas.

[David Aubke]

Are the keys getting caught on the front lip of the piano case?  If the tolex is loose and bulging out, it can catch a key.

Ooh. That's a good one. That happened to me once. Took me like a half hour to figure out what was happening.

[dlux]

I moved some keys around and the same notes have the same problem. Can't see or feel any problem with hammers. Now I'm really confused . Any other ideas ? Thanks- Dlux

[David Aubke]

Well, somewhere something is hanging up. I'd say it's going to be up to you to determine where the friction is.

[Cormac Long]

I have a hammer (half-wood '75) on my upper register that appears to stick in the same scenario. If I press the key with the damper held down, it will stick for several seconds and release.

In my case, if I lift the key back to rest position, the hammer remains up, but falls back in a few seconds. I haven't investigated it in detail yet, but I asume the hinge is a bit stiff or damaged. I'll need to remove the hammer and take a closer look at the hinge in case there's something blocking it or its damaged.

Another test, one I plan to try myself, is remove the key from the problem hammer and one adjacent to it. Then with the sustain held down to release the bridle tension, lift both hammers manually and release or just move them up and down to feel for motion differences. This may help visually highlight a stiffer hinge movement on the problem hammer.

[pianotuner steveo]

If the sticking is in the same spot even if you switch keys, then it could be the front rail pins are turned sideways. They are oval, and if turned, can catch on the bushings. Or it can also be loose tolex catching as suggested before. The balance rail pins are round, turning them would not be any help.

[dlux]

My front rail pins are straight . I can't see or feel anything going on with the hammers other than the fact that when you play them with the the harp up they don't bounce as many times before the return to the resting position.  Should I try a few new hammers or perhaps replace the key combs in question ? What do you fellas think ? Dlux

[dlux]

Never mind about the key combs . This piano  has the half wood hammers with the flanges.

[Ben Bove]

The keys behave normally without the sustain pedal pressed.  Then when you press the sustain pedal they stick.  This means the keys are sticking a little bit, and the little bit of tension pull from the dampers when you release the key is helping to return the key to normal position.  It's just enough - and when that tension isn't there (when pedal depressed), the slightly stickiness gets no aid from the damper pulling it back.

The Vintage Vibe guys are right on about the bushings being swollen, or hanging up the keys.

The easiest way to test this is in rested position, wiggle the key in question left and right.  Is there a little bit of play that you can move the key slightly both ways, or is it rock solid won't move?  Then, when you depress the key same thing - in the depressed position can you wiggle the key left and right, or is it rock solid there's no play left and right when depressed.

If there's  no play in the key it's too tight around the key pins.

A barbaric way to ease the bushings is to grab the key and pull it to the left or right as you're depressing it, basically using the front key pin as an easer.  I don't really recommend that but it gets the job done.

[Kim Jinkings]

I have two keys that behave just like that. Lube those guide pins correct the problem for a while. So, I periodicaly need to lube...and it's fine. I use the vintage vibe's lube

[cfishel15]

Another "barbaric" thing you can try is to remove the key bushing felt, then VERY CAREFULLY use a Dremel tool with a fine conical grinding tip to remove a VERY SMALL amount of wood. Then you can re-felt the slot. This worked well for me after numerous unsuccessful attempts using the key bushing tool to ream out slots. With that tool, you can compress the wood only so much before it cracks!