Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Persistent problem/Hammer shank flange centers??

On a new grand (5 months) on a number of keys you hear a faint click when slowly depressing those keys. The click appears when the hammer is high up (close to or at release). If one presses the keys repetedly the click disappears or gets less audible; waiting a few seconds and pressing the same key again, and the click is back. It cannot be related to the dampers because you hear it also with the right pedal down (dampers up).

I suspect free play in the flange centers because the action was lubricated three times and there is also no friction at the knuckles. By coincidence this problem showed up just after a first regulation when the let-off was set closer than the factory setting.

I read somewhere that shank flange centers are often a cause of clicks. Should I just leave it like that and hope the problem goes away spontaniously or could continuing playing aggrevate it over time?

schwammerl.

Factory let off settings are usually excessive.
Lube at the flange three times suggests excessive friction - tight centers. Lack of friction at the knuckle could mean the repetition lever is too high and or the repetition lever spring tension is too strong. In this case the click could be the jack as it makes a hard return into it's seat just after let off when the key is slightly released.
Normally if let off is changed then so should the drop, aftertouch, rep lever hight, and jack/knuckle alignment.

A new grand should not have hammer flanges loose enough to click. (having said that, there are some brands where anything is possible). However, centers do not usually click when the key is slowly depressed, nor is it something that goes away after the key has been played a few times.

It sounds more it is the repetition spring. I don't think playing on it will aggravate it. Keep notes on which keys are affected, and point it out to your tech at the next tuning, which should be very soon (remember a new piano should be tuned four times in its first year.)

The jack position needs to be adjusted would be my guess if anything needs to be done. The click at letoff is what you want. It's more of a feel than a sound. New owners tend to fixate on small sounds the piano makes when not being played. Play a note and see if you can hear the click. Chances are in the exaggerated situation you put the note through, all you hear is the normal workings of a mechanical action. There is no way to make it completely quiet.

Thank you all very much for the response.
As from the comments (Gene, Supply) the repetition spring is involved. After closer check, the click actually appears even earlier: at the time the jack makes contact with the knuckle, so before escape.

If a spring is too tight wouldn't it loosen up automatically and gradually just by extensive play in the future?

P.S. what Gene pointed out, the other adjustments which need to done after let off change (drop, aftertouch...), were taken care off.

schwammerl.

Another possibility is the leather/drop screw interface. The drop screw comes into contact with the leather at the same time the jack releases from the knuckle. Teflon powder could be applied to the leather to eliminate it if that's the problem. Sometimes this gets overlooked in action lubrication.

As others pointed out, it could be a rep spring issue.

I wouldn't think it would have much to do with tight centers. There would be other problems associated with that--like very poor repetition and loss of power.

The jack is always in contact with the knuckle from the start of the keystroke. What you are hearing is the pad on the end of the rep lever contacting the drop screw which should happen right when the jack toe hits the let off button. Just a fraction of a second before letoff. You don't hear this while playing. It is a fact of actions. They are not completely quiet.

If you hear this click while playing, please tell me.

I vote for a noise from the repetition lever pad touching the drop screw. Rub a little Teflon powder into the pad to stop this.

Another possibility: If this piano has an aluminum hammer rail and a wood letoff rail, check that the letoff rail is not loose. You need to remove a few hammer flanges to tighten the screws from above usually.

Don Mannino

Thank you all again for your comments.

The cause was neighter (as I initially suspected) the hammer shank flange centers, nor (as suggested a few times) the contact between drop screw/repetition lever pad (lubrication with teflon powder had no effect).

I solved the problem by "trial an error": just by "easing" the repetition lever, i.e. pushing down and letting come up again every lever in the mid section some 20 times, the clicks are gone. So presumably too tight repetition spring in some of the keys or the rep. lever flange.

schammerl.

Repeated lube of the jacks and then more clicks could mean lousy bush felt.

Could be that your action in pushing down the balanciers caused the springs to flatten out whatever irregularity might have caused the noise. Thanks for the update.

Update.

The clicks went away ideed after repetitive pressing of the repetition levers, however that didn't last longer than 36 hours; after that they were back!

I now released all repetition springs from their fitting in the repetition lever and lubricated the top of those springs with teflon powder and put the springs in again. The clicking is over again!
I however wonder how long it will last this time. Till the lubricating action of the teflon powder is over and the powder has fallen out off the spring/lever slots?

schwammerl.

Maybe what you should do is remove a whippen and look at the slot where the repetition spring seats. It may need cleaning or shaping.
Also, polish the part of the spring that seats there.

How long? Your guess is as good as ours. Maybe forever. Please let us know if they stay away. The rep spring groove is a hard one to lube properly.

I would think the Dupont TFL 50 spray might be good here...?????

Nelson"s slot can be burnished with a pencil lead rubbed in the grove.

The initial faint clicks in nearly all keys which I described initially have now finally been taken care of by an independent tech (called in for a complete regulation):

there was a greasy deposit (likely due to the use of inadequate lubricant) in the groove where the repetition spring fits into the repetition lever; he cleaned the grooves and lubricated the springs with ProTek.

There is however one persistent problem which he apparently could not solve.

When the grand piano hasn't been played for a couple of hours and when then after depressing the middle C, that key is released quickly, you hear a very disturbing rather loud click. Often this disappears after the key has being played e.g. 10 times; it may also last longer, go away for a few strokes and come back again. One can induce the problem if the key is playing normally by first holding it down with some force and the releasing it.

The tech thought it was perhaps the key bouncing back against the key stop rail. He therefore increased slightly the height of that rail above the keys. We thought that solved the problem, but soon after he left, the click was there again. (I must say I found it strange it would have something to do with the key stop rail height, as I would the expect clicks on many more keys)

Must say I don't know what to do now. Call in the indepentent tech again to further look into it...or have the dealer check it (under warrenty) and expect him to find a solution. I wonder though if he will know the cause!

Anyone any ideas?

Many thanks,

schwammerl.

The other half of the rep spring is the jack spring.
I would think that click would be the jack slapping the stop felt but the spring might not be seated properly in the hole on the jack. I say the just because you were working on the springs and out of 88 of them, this can happen easily

Did you recheck the rep spring groove on the C?

Thank you Keith for responding.

The spring fits nicely in the hole (lined with bushing) of the jack; the upper part of the spring is also in the groove of the repetition lever.

In fact that particular key (middle c) also does not show these faint clicks on slowly depressing (about halfway) that key.

What persists for the middle c is that quite loud click during quick release after it was depressed.

schwammerl.

What I was saying was that whatever was causing the sticking could have moved so that when the rep lever releases, the tick is coming from a different spot in the action cycle.

When you release the key and the hammer is in check. The key slaps the backrail cloth, the rep lever slaps against it's stop and so does the jack. If the hammer stop rail has too much clearance, the hammer tail can sometimes hit the wippen screw.

Very rare, but could be likely. If the end of the rep spring that goes into the tiny hole in the rear of the jack is too long(by as much as 1-2mm), and the piano is in a humid environment. The end of the spring can be contacting wood in the jack where it should'nt be. This can cause a click on realese that will come and go. I've found this on several very expensive pianos using Renner parts. Once the springs were trimmed, the clicking stopped.