CAUT

Expand all | Collapse all

Loud key clatter on release

  • 1.  Loud key clatter on release

    Registered Piano Technician
    Posted 08-14-2019 23:54
    I have a customer whose 1920’s Mason & Hamlin B has a loud key clatter on release.

    It’s an “average” rebuild: soundboard shimmed, new strings and pinblock, new h/s/f and wips, everything else original: back action, etc. Keys have been rebushed, not too loose, and the ivory is tight.

    My first suspect was the back rail cloth, which was original and in terrible shape. I replaced it today with new Kluge cloth, keeping the two original thin red felt inner pieces, and gluing down just the edges. This has been very successful on several other pianos.

    On this piano, it made no difference at all. What should I check next? It’s noisier with the action in the piano than outside it.

    —Cy—


  • 2.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 00:31
    Cy

    With the new wippens, are the capstans hitting in the middle of the wippen cushions?  Sometimes the configuration is such that the capstans are just barely on the cushions, which will create a clack.

    ------------------------------
    Willem "Wim" Blees, RPT
    Mililani, HI 96789
    ------------------------------



  • 3.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 01:20
    Hi,  Cy,

    Chucking keys?  It doesn't take much to make noise at the balance bottom hole.

    Bill

    Sent from my iPhone





  • 4.  RE: Loud key clatter on release

    Posted 08-15-2019 06:36
    Loose Kel leads?

    ------------------------------
    Douglas Mahard
    Bethlehem CT
    203-266-6688
    ------------------------------



  • 5.  RE: Loud key clatter on release

    Posted 08-15-2019 06:55
    Back rail cloth that is glued along the front and back makes for a harder landing. If the back of the cloth is glued down, cut it loose. It is best to only glue along the front edge.
    I had that complaint on an old M&H grand. I cut the back loose on the original cloth to no significant noise reduction. Replacing the cloth and only glueing along the front edge did the trick, underfelt is advised..

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 6.  RE: Loud key clatter on release

    Posted 08-15-2019 07:09
    Hi Cy,

    Does the key clatter if you hold the damper up?
    Is it possible that one or more of the damper flange weights have come loose enough to rattle?
    Maybe the damper flange itself is a bit loose, or the sostenuto rod?

    These clatters can really drive you nuts! Good luck hunting it down!

    Jeff

    ------------------------------
    Jeffrey Cutler
    Stillwater MN
    651-398-6293
    ------------------------------



  • 7.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 07:12
    Did you tighten the wippen flange screws?

    ------------------------------
    Jason Cassel, MA, RPT
    Piano Technician
    BYU School of Music
    HFAC C-109
    (801)422-3400
    ------------------------------



  • 8.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 08:09
    Loose hammer rest rail? New wips hitting rest rail or wip rail? Backchecks hitting sostenuto knife (would stop completely if pulling out action)?

    ------------------------------
    Greg Graham, RPT
    Brodheadsville, PA
    ------------------------------



  • 9.  RE: Loud key clatter on release

    Posted 08-15-2019 09:01
    Then there's at old dense jack rest felt.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 10.  RE: Loud key clatter on release

    Posted 08-15-2019 09:24
    All of the above plus check whippen heel cloth too dense slide  a single edge  razor blade under the felt to improve this... BUT also I would check  the pinning on the whippen flange that maybe is too free and try repining a sample   at least one half size larger pin, have repinned many 80's vintage small Baldwin grands and a couple of  newish smaller  Bechstein grands with this symptom......martin.
    www.snowpianos.com

    ------------------------------
    Martin Snow
    South Burlington VT
    617-543-1030
    ------------------------------



  • 11.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 10:15
    Probably not knuckles with new parts (and not with more noise in the piano than out), but certainly hard knuckles make for a lot of return noise. Most often, it tends to be several things all in combination. For diagnosis (elimination of factors), it's useful to put the action on the bench, raise a hammer and drop it, do the same while supporting the key in up and down positions. Raise key front and let it fall. Same for key back. With hammers up, raise wippen and drop, supporting the key in both up and down positions. 

    Then you proceed to inside the piano things. Did anyone mention glides possibly being high?
    Regards,
    Fred Sturm
    "Art is not a mirror held up to reality, but a hammer with which to shape it." Brecht






  • 12.  RE: Loud key clatter on release

    Posted 08-15-2019 14:18





  • 13.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 21:08
    Loose underlever leads?

    ------------------------------
    Susan Kline
    Philomath, Oregon
    ------------------------------



  • 14.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 10:28
    Cy,
    Check if the back checks are contacting the sostenuto rod, just pull the action out slightly to check.
    I had this on a few Mason & Hamlins.
    John

    ------------------------------
    John Zeiner
    Allentown PA
    610-437-1887
    ------------------------------



  • 15.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 10:35
    Hard knuckles?
    Oversize key holes?

    Keith Akins, RPT
    Piano Technologist
    715/775-0022 Mon-Sat 9a-9p
    Find me on LinkedIn





  • 16.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 11:25
    Thanks for all the great suggestions and the diagnostic tips.

    I did glue both the front and back edges of back rail cloth down, as was there originally. And as I did, I had the vague memory of one edge being loose (like damper lift tray felt). I’ll cut the back edge loose.

    I had a weird click with the action out that took a long time to find, made by lifting one hammer and dropping it. The tail was hitting the top of the wippen flange. So new individual hammer rebound cushions wouldn’t hurt.

    If the knuckles are hard, would needling the felt underneath from the side help? I often brush the leather with a suede brush to restore nap.

    I’m going to try (just as an experiment) turning a few front rail pins. There’s not much side play, but the pins are not far into the bushings when the keys are at rest, so there’s certainly an opportunity for them to bounce around.

    Backchecks on the sostenuto blade are another good test. I’ll follow up.

    —Cy—




  • 17.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 16:11
    Could also be a loose glue joint somewhere. Do the keys clatter when the action is removed, or only when it's inside the piano?

    Edit: I see from the original post that it is still making noise when the action is out, but not as loudly as when it is in. Ok, that rules out the sostenuto rod theory. 

    ------------------------------
    Benjamin Sanchez, RPT
    Piano Technician / Artisan
    (805) 315-8050
    www.professional-piano-services.com
    ------------------------------



  • 18.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 20:06

    Hammer tails on wip can be quickly fixed with a small, cylindrical dremel grinding bit and shop vac. Quicker than messing with hammer rest felt, if it is at normal height already (should be, if wips are new).  Sculpt away the underside of the tail that is in way.





  • 19.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 18:15

    Cy,

     

    I vote with Bill Shull, I almost always find that the balance holes are just a little too loose. I use a sharpened small dowel dipped in boiling water to dab the water into the hole, let them dry, then ease them until they are just a little on the tight side.

     

    Other suggestions also – balance rail felt punchings could be original maybe and overly hard. But if the balance holes are snug the noise is still usually taken care of.

     

    Wippen cushions for sure can make noise – but you can check that by lifting up the wippen and dropping it on the key.  Same with the knuckle, but that is usually more of a 'Clack' that isn't affected by being inside the piano.

     

    Don Mannino RPT

    Sent from Mail for Windows 10

     






  • 20.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-15-2019 18:57
    Only related - I had a Yamaha C7 today with one key clicking (not a clatter). Thought I had it with softening the jack stop felt but found that this piano has no felt at the back end of the keys.
    The felt was on the under side of the damper levers, similar to butt felt squares. One of these had torn in 1/2 and the remaining felt was crispy with glue. Replaced the little felt and click was gone.
    Nancy Salmon
    LaVale, MD





  • 21.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-18-2019 10:40
    Don wrote: "... then ease them until they are just a little on the tight side."

    Don,

    When lifting keys a couple of mm at the front and releasing them to note the speed of their fall, what speed of fall would you consider, "...on the tight side"? (This test for balance hole snugness depends, of course, on the balance rail key bushing being free.)

    Thanks,

    Alan


    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 22.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-18-2019 14:28
    I'm not Don, but I'll note that this is tricky to check with grand keys that have lots of front lead. I always lift the back of the key, while supporting the front in its up position, minimizing the weight of the key that is acting against the friction. I look for a smooth fall with a little hesitation.

    The best way I have found for controlling balance holes in general is precision reaming (parallel fluted) to .001" wider than the pin, followed by application of the tapered burnisher (as I'll call it, easer being another term), pressing pretty lightly to make the hole tapered. This allows for fast and consistent work. .001" leaves the holes tight, consistently. So I am crushing wood a bit to ease the hole I prefer that, as it allows for RH changes.

    If the reamer does nothing, is completely free in the hole, it needs to be sized.

    This reminds me of a related question I've been pondering. Some piano keys have a slight bevel at the bottom of the balance hole, so that the narrowest part of the hole is maybe midway in the 3 mm or so mortise. This led me to wonder if maybe that wasn't generally a good idea. The key rotates on the balance rail punching, which means that when it goes down, it is compressing the front of the punching, and actually pivoting at a point in front of the pin. Thus, the part of the key in the center of the balance hole is going up and down on the pin -  a tiny bit, but it can be significant. 

    Since the key is rocking, having the bottom and top of the hole tapered seems like it might be at least marginally a better design. Any thoughts out there?
    Regards,
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou






  • 23.  RE: Loud key clatter on release

    Posted 08-18-2019 15:56
    I made a gage for production work on easing the b/r holes:
    (I'll describe each photo when I see in which order they appear)

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 24.  RE: Loud key clatter on release

    Posted 08-18-2019 16:15
    There are two brass machine screws.
    Photo 1
    The underside of the gage. The shank in the plug is the bottom of the platen, I cut a slot for adjusting with a screw driver. The oval head screw's hole is counter sunk for elevating the shank above the top surface. (as seen in photo 4)
    Photo 2
    The depth of the large platen is set for the easing tool to allow the tip of the tool to protrude to ease each key identically. It was a round head screw which I fixed into a drill and ground it flat on a belt sander.
    Photo 3
    Shows the platen lowered for easing tool protrusion with the rear screw shank flush with the surface.
    Photo 4
    Shows the rear screw elevated for balance rail holes that are chamfered for reaming the hight of the b/r hole. If there is no chamfer, both the small screw and the platen would be flush with the surface for the height reaming tool.

    When doing real production height reaming, I place the reaming tool in a drill. I place two keys on a strip of metal and insert the tool and power away. Much faster than hand work in the field.

    The ink line on the side is a quick index to align the tool with the platen.

    I don't think there is a benefit to chamering the b/r hole from the bottom. In my opinion it would cause the bottom to scrub along the punching and increase friction. The key should pivot from the bottom of the keystick.


    PS. I don't make these, this is the first and only prototype.
    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 25.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-18-2019 22:37

    Alan,

    How does one describe it?  It's easier to demonstrate.

    • For best performance and tone in a performance instrument, but not reliable for most home pianos, I recommend that the test be done with the action stack in place. Lift the key front so the balance bushing is at the top of the key pin, then release. It should take maybe a second to glide back to rest.
    • This means with the stack off, you have to balance the key weights with your hand and rock the key slightly, and it will slide down to rest, but slow.  The bass should be tighter than the treble.
    • For most home pianos, the above test is done without the stack, with the same speed.  Once again, you usually have to hold the front of the key, especially in the bass, to offset the key weights.

     

    So let's say the velocity of key slide is 2mm per second? 😊



    ------------------------------
    Don Mannino RPT
    Kawai America Corporation
    ------------------------------



  • 26.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-19-2019 00:55
    Thanks for the explanation, Don. I used to make them freer than that, but more recently have arrived at the same standard you describe. There are those who maintain that the balance holes can be even tighter than that without repetition suffering. That notion has a certain appeal where noise abatement and longevity are concerned, but I have yet to try going any tighter than what you and I are talking about.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 27.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-19-2019 16:06

    Cy,
     
    I vote with Bill Shull, I almost always find that the balance holes are just a little too loose. I use a sharpened small dowel dipped in boiling water to dab the water into the hole, let them dry, then ease them until they are just a little on the tight side.
     
    Other suggestions also – balance rail felt punchings could be original maybe and overly hard. But if the balance holes are snug the noise is still usually taken care of.
    Donald Mannino,  08-15-2019 18:15
    And this was the winner! Several people suggested this problem. Mannino-sensei, your solution worked beautifully. I removed the keys, put them upside-down in the action cavity, broke the lead tip off a pencil, and used it to moisten each hole. Don't use more: it can drip down into the bushing and loosen it. I let them dry for half an hour, and reinstalled.

    I left the keys much tighter on the BR pins than I normally would (where they climb the pin if you lift at the front), to be sure of a fix, and to my surprise, there wasn't much of an increase in friction (just going by feel, not measurement). Don, your specifications for performance and home pianos were very useful. I've been leaving them much looser. Just to be clear: with lower humidity, wood shrinks, and BR holes will be smaller?

    A useful diagnostic was to push down on the key at the BR bushing while releasing it. This made it noticeably quieter. Also, listening carefully to one key at a time made it clear that the sound was different on each one, eliminating the likelihood of a wholesale fix like new back rail cloth. Testing the top octave eliminates the back action and sostenuto blade.

    Other useful tests to isolate parts:
    • Drop the hammer with the front of the key held up
    • Hold up the wippen and drop the front of the key, then the back of the key
    • Flip up the hammer, drop the wippen with the key held up and then down
    • Remove the top stack and put it in the action cavity or bench. Drop the hammer.
    For reference, here are all the other suggestions I received, and their effect on this piano. I found the loudest key and a quiet one, and compared them.

    • Cut loose the back edge of the back rail cloth
      • This made a slight improvement for the keys on the bass bridge, but nowhere else
    • Loose hammer rest rail
      • This is the most frequent culprit. When tightening the round slotted nuts, be sure that the nuts underneath are in their correct position to support the rail. If they're too low, the flexing of the rail as you tighten the top nut can give a false sense of security.
    • Loose key stop rail
      • Ditto on the lower nuts.
    • Hard knuckles
      • Dropping the hammer while lifting up the wippen eliminated this
    • Hard wippen cushion
      • With the hammer lifted, dropping the wippen on the key was a good test. There was no hammer rest rail, so it was easy to remove it and slice horizontally between the heel and its felt to create an air gap. It made no difference.
    • Underside of wippens hitting the wippen flange rail
      • This would be loud! Easily tested by raising a capstan to increase clearance.
    • Hard regulating button felt
      • Easy to test by flipping the jack and releasing quickly.
    • Misalignment of wippen cushion to capstan
      • This would be loud if the capstan were hitting the side of the wip. Inspecting the cushions was an easy diagnostic. They were all dented in the middle.
    • Hammer tails hitting the wippen flange or backchecks
      • I had one note clicking on the wippen flange. It's a loud click! Dropping the hammer while holding down the wippen to isolate it was a good test. Sanding the tail fixed it.
    •  Back action issues -- all easily diagnosed by pulling the action
      • Loose underlever leads - none found.
      • Backchecks hitting the sostenuto blade.
      • Hard key end felt. Test in the piano by testing the top octave.
      • Loose underlever flange.
    • Loose key leads
      • None found.
    • Hard nameboard felt between the fallboard and keytops
      • Pull the fallboard to test.
    • Pinning on all flanges, especially wippen flanges
      • I did not test this, but the wippen flanges were loose -- definitely could not support a nickel (five grams).
    • Hard balance rail felt punchings
      • I noticed about a ten percent improvement on my one loudest note. Certainly an easy thing to try, with multiple benefits.
    • Keyframe glides too high
      • There was no knocking at the balance rail.
    • Loose wippen flange screws
      • I tightened them, to no effect. And loosened one as a test -- no difference.

    Much thanks to this large community with enormous experience, and the generosity to share it.

    --Cy--

    ------------------------------
    Cy Shuster, RPT
    Albuquerque, NM
    http://www.shusterpiano.com
    ------------------------------



  • 28.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 17:02
    Cy, you missed one that was mentioned, loose damper under lever leads. (of which I've run across exactly one in 43 years)

    ------------------------------
    Steven Rosenthal
    Honolulu HI
    808-521-7129
    ------------------------------



  • 29.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 17:30
    Only one incident of loose underlever leads in 43 years, Steve? You must lead a charmed existence! I have encountered them on various makes, but as the bulk of the Yamaha grands at our school approached the three decade mark, those underlever leads started rattling and walking so much that we wound up going through all of the Yamaha grands and swaged all of the underlever leads. (BTW, this is about the same timetable for loose pedal lyres on the same pianos.)

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 30.  RE: Loud key clatter on release

    Member
    Posted 08-15-2019 20:41
    How about the felt under the fallboard which may be too thin , worn or caked with hard glue. I would concentrate on the loudest keys and work my way through it following every suggestion made here. While you are at it check the pinning on all of the flanges but do every repair one at a time. You could have a number of problems stacked atop others. I had a mason that was rebuilt but making noises when ever the key was pressed . it turned out the old front punchings were hard from time. Customer did not have the action redone but had case, pinblock, strings, damper felts. At some point if you follow the list of things the noise will stop then you can go do that step on another noisy note and its down hill from there.

    ------------------------------
    James Kelly
    Pawleys Island SC
    843-325-4357
    ------------------------------



  • 31.  RE: Loud key clatter on release

    Posted 08-19-2019 17:31
    I am getting to this a bit late, but if I may add my comment:  I was taught that keys should have a "suction fit" on the BR pins. If they simply drop down on the pins, they will bounce at the balance rail. This is what causes the noise.

     But also of importance, when the keys do not have a snug fit on the pins, this can lead to chucking. (Once there is a little play, it tends to become greater quite quickly).

    ------------------------------
    Jurgen Goering
    ------------------------------



  • 32.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-19-2019 20:34
    Isn’t it true that the balance rail is the only place in the action where a moving wooden part contacts a metal part directly? It seems possible to design a longer-lasting, more humidity-resistant interface for such a critical element of friction, energy transfer, and sound.

    —Cy—




  • 33.  RE: Loud key clatter on release

    Posted 08-19-2019 20:51
    Like so many other things, it works and has worked for centuries.  Any improvement would probably involve a complicated or costly solution. Think of tuning pins - what a primitive system, but it works and is a good balance between functinality and cost/complexity. (Contrast with the M&H screwstringer system)
    That said, with today's plastics there may be a solution on the horizon. Chuck Behm is working on FR mortice inserts that are digitally printed plastic units, for his outdoor piano project.

    ------------------------------
    Jurgen Goering
    ------------------------------



  • 34.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 01:30
    Actually, there have been alternatives. Believe it or not, the Lindner piano had a spring clip sort of thing that held the keys and flexed -- rather than having friction at hole and bushing. (I realize that the Lindner had its limitations and was made to a particular price point and marketing concept -- being made lightweight so it could be airfreighted worldwide from its factory at Shannon Airport in Ireland -- and they got caught by the use of plastics that eventually fell apart but it was more of a genuine piano than other objects purported to be pianos such as those escaping from the Aeolian factory in Memphis.) 


    Responding to your previous post summarizing a compendium of noise factors (and a very good job, too): 

    What hasn't been mentioned here is that it is important to understand that there two or three principles at play here which are somewhat opposed to each other -- primarily joint rigidity and friction. A similar situation is present in the hammer shank action centers. The joint ideally should be very rigid -- and if it is not there is tonal degradation. But it ideally should also be free to move with minimum resistance. As it happens  with felt action centers, the the Goldilocks Zone is about 5-7 swings of the flange/shank/hammer assembly.  More than that and rigidity is inadequate for good tone... less, and the shank won't move freely. BUT this isn't an absolute parameter -- only for felt action centers. With WNG rigid centers, the joint is almost perfectly rigid but much freer than a felt-centered shank assembly, so there can be many more swings with superior rigidity that is audible. 

    Same for the keyhole/keypin joint. If it is not rigid, there will be noise and where there is noise there is energy loss. But too tight and the key doesn't move. So you get parameters like "suction fit" or the one Don M provided earlier. And those are good descriptions of the joint consisting of clean pins and good bushings and properly sized holes. But if the pin is properly lubricated at the hole (I use McLube), the "rule-of-thumb" parameters change. Now you can have quite a tight fit without excessive drag from friction at the pin hole. Lubricating pins -- both at the top where the bushings rub and at the bottom where the hole is -- is part of my standard protocol for basic action maintenance. It's all upside and no downside. 

    There are other factors, as well. One (which has been mentioned) is the shape of the inner profile of the hole.  If it is cylindrical, there will tend to be binding whereas if it is conical there won't be any binding.
    Another is material. Hardwood, like maple, is simply the wrong material. If it becomes loose, it is noisier than basswood or spruce -- which are actually slightly "resilient". It is also more difficult to repair or adjust by any kind of "sizing" procedure.  Perhaps the best solution is a shoe of spruce. Another aspect of material is grain orientation. If the end-grain is presented to the front and back sides of the pin there is greater strength than if another grain orientation exists. 

    My point is that rules-of-thumb can be helpful but it is even better to fully understand the opposing criteria that lead us to find the appropriate "sweet spot". 


    ------------------------------
    Keith Akins
    Akins Pianocraft
    Menominee MI
    715-775-0022
    ------------------------------



  • 35.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 07:30
    Excellent post Keith!
    Thank you!

    Debbie Cyr
    Registered Piano Technician
    508-202-2862 cell
    Debbiecyr@me.com

    Sent from my iPhone




  • 36.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 10:31
    I agree, great post, Keith!. And I agree that lubing the balance hole is a good idea. I apply McLube with a pipecleaner, usually with all the keys in key clamps. Takes a minute.

    What we need to realize is that this is more complex than it seems at first glance, kind of like hammer/string interaction. The hammer almost always contacts the strings more than once (almost, because this may not be the case at the top treble), and knowing that can give us a better idea about voicing, and particularly about what we tend to call pre-voicing.

    Similarly, a key rocking on a balance rail is not entirely straightforward. The center of the balance pin is rarely the actual fulcrum point. The center of rotation moves forward as the key goes down. How far forward depends on the condition of the punching on most pianos: if it is fairly soft and resilient, it will compress, and the fulcrum will stay close to the middle of the pin. Harder, denser felt will mean that the fulcrum will move forward, perhaps quite a bit. Smaller diameter punchings will mean less movement of the fulcrum point. )Less dense felt will compress over time, causing key level to be unstable, so there are tradeoffs). 

    If the fulcrum point moves, that means the key will rise on the pin as the front goes down. The feel of the result can be increasing resistance at the bottom of the key stroke, a spongy feel. This is exacerbated if the hole is cylindrical, and it can reach the point of being very noticeable. It can easily lead to the pianist feeling like the bottom of the keystroke has been reached, resulting in less actual dip than what was regulated, and reducing or eliminating aftertouch, somewhat like when a damper upstop rail is set too low. (With the action stack off, you can sometimes see and feel this with the keys being held above the punchings: you can push them down, but there is some resistance).

    It is possible to make the fulcrum lie at the midpoint of the balance pin by gluing on a half card punching on the bottom of the key, as is sometimes done to change the key ratio. It could also be done with the Steinway style balance half round thingy, by cutting away material just forward of the center. 

    Concerning sizing the hole, parallel fluted reamers make this fairly easy and permanent, but there are caveats. My first exposure to those reamers was at the Steinway factory (Academy) maybe 15 years ago, and they used reamers .002" wider than the pin. This made for a fairly loose fit if you rotated them until the tool moved freely in the hole: the key would drop without resistance/friction. When I got home, I got one the size of the pin, which required a good bit of easing with the taper tool to reach the desired behavior. So I went to .001" over size, which requires just a bit of easing. Pianotek sells them .0015" over size, and this is a little looser than I'd like for long term. If you aren't too vigorous in turning it, the size will be about right. (Machining wood isn't as precise as machining metal or plastic. There are varying amounts of raised but uncut fibers on a microscopic level).

    I have also done sizing using heat: a pin the size of the balance pin in question, inserted in a short length of 1/4" brass stock, used in a heat controlled soldering iron. This can be useful for old keys, where there are a lot of fibers sticking up. A little glue size followed by heat yields a better, more solid result.

    Someone asked about RH effects. Yes, the hole gets smaller when the conditions are dry. All new pianos I have dealt with here have tight balance holes within 2 - 3 months (due to our low RH, 20% and below much of the year). OTOH, if the holes have been "eased" (wood compressed with the taper tool), this behavior will vary. The compressed fibers are likely to swell with higher RH, just as they will swell if you apply steam to remove or resize bushings. IOW, the fibers will return to their original configuration to a large degree. This is one reason I decided to ream all balance holes as standard procedure. In the process of steam sizing or rebushing, I have much less work to reestablish the balance hole configuration. (Actually, what with lubricated bushings and pins, and steam resizing of bushings, I have done maybe one rebushing job per year the past several years, on an inventory of 95 pianos, WAY down from 20 years ago).

    In any case, it is worthwhile to bear this complexity in mind when dealing with keys, rather than just follow a given procedure. There are a lot of possible factors involved, and many ways to address them.
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel






  • 37.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 10:15
    It seems that the primary function of the BR pin is to keep the key from moving fore-and-aft.

    I may try a drop of silicone caulk at the bottom of the key. If it stays flexible enough to allow key movement, the hole could be much bigger than the pin, never making noise. And you wouldn’t need the felt bushing on top, or the shoe to hold it.

    —Cy—




  • 38.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 12:21
    Hi-

    This is only a last resort, quick solution- but in cases where sizing of the hole did not work out for any reason and you get a little click noise at first movement of the key, then try a very small dab of CLP gel on the pin right where the hole contacts.  This is not my preferred repair mind you, but in a pinch it will fix the noise every time. 

    Dennis. 
    --
    Dennis Johnson
    Piano Technician / Music
    Office: 507-786-3587Mobile: 612-599-6437 
    1520 St. Olaf Avenue Northfield, MN 55057






  • 39.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 12:28
    Dennis,

    Couldn't find "CLP gel." Were you referring to MPL-1?

    Thanks,

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 40.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 12:41
    Hi-

    No, It's the Protek CLP lube in gel form, as opposed to liquid. Good stuff, and I presume Pianotek still sells it but I bought mine years ago. 

    Best,
    D. 
    --
    Dennis Johnson
    Piano Technician / Music
    Office: 507-786-3587Mobile: 612-599-6437 
    1520 St. Olaf Avenue Northfield, MN 55057






  • 41.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 12:47
    Thanks for the clarification, Dennis. I did not see CLP gel on the Pianotek website.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 42.  RE: Loud key clatter on release

    Member
    Posted 08-21-2019 18:48
    I have the reamer tool sold by pianotek and it can be quite helpful with balance rail hole issues. To ease the balance rail holes I do not use the supply house tool but have a Flugelbauer tool that is tremendous because of its shape and feel. i had a very stiff action in a K Kawai 500 that I eased the keys with ever so gently. It made a huge difference....

    Regarding balance hole repairs and chucky keys- be mindfull there is an insert kit you can buy that will do wonders to noisy chucky keys. Finally I am not sure I would use silicone or any other substance to try to quiet a noise. Sooner or later the forces front and back and side to side will compress or distort the whole. I stopped using PVCE glue on key bushings and dont know where or when I got the idea it was the stuff to use. I found that it often oozed out and its rubbery texture after drying hung things up. Far better results now using fish glue or hot hyde . If you are having problems in actions that have aluminum rails keep in mind that sound travels and gets amplified in those actions. I have not experimented yet but I believe some rubber washers/grommets/acoustic foam strips could reduce action noises significantly. This is the same principal now being used in appliances such as dishwashers. The db levels have been reduced to low low levels by sound insulation and adding rubber standoffs , sound absorbent materials .

    ------------------------------
    James Kelly
    Pawleys Island SC
    843-325-4357
    ------------------------------



  • 43.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-21-2019 19:52
    Alan, I guess that's a blessing of being in the tropics where the rh rarely dips below 45% and is mostly between 50 and 70%. Things don't tend to get loose. That said, I'd gladly deal with some loose parts than the expanding lead weights we run into frequently, they can expand to the point that they split the key sticks.


    ------------------------------
    Steven Rosenthal
    Honolulu HI
    808-521-7129
    ------------------------------



  • 44.  RE: Loud key clatter on release

    Registered Piano Technician
    Posted 08-23-2019 14:09
    Alan-

    Sorry, but I just had another order with Pianotek and cleared up my own confusion.  I was wrong. The label on my jar of lube is completely worn off but I confirmed now it was indeed the MPL-1 that I had in mind.  My bad.  

    best,
    dennis.

    ------------------------------
    Dennis Johnson, R.P.T.
    St. Olaf College
    Music Dept.
    Northfield, MN 55337
    sta2ned@stolaf.edu
    (507) 786-3587
    ------------------------------