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Does anyone have a protocol for bedding the action so that key dip remains accurate?

  • 1.  Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-22-2024 15:40

    Hello fellow members,

    I have noticed that even when I painstakingly bed the action to be as accurate as possible, the key dip will change almost every time I re-bed the action. I do use the Edward's Action Caddy to set an accurate key dip when I regulate out of the piano. I have noticed that even the most minute change in the action caddy setting will change the key dip, which tells me that key dip is ultra-sensitive to any minute changes in bedding the action.

    My question is this. Does anyone out there have a protocol for a key dip priority bedding of the piano, where they bed the piano in order to reproduce the exact key dip they originally set on the keys?

    Thanks!



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------


  • 2.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-22-2024 15:45

    Joe,

    In my experience it's the other way round. Bed the keyframe in the piano, then use your dip measurement to reset it outside the piano.

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 3.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-22-2024 15:52
    I do it the way you say Peter. But after bedding the action and setting my desired key dip, then taking the action out of the piano to work on it, I have to rebed the action when I put it back into the piano, because the bedding is off. It is then that the dip has changed from where I previously set it. So I am wondering if some techs have come up with methods to solve this problem.












  • 4.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-22-2024 16:02
    No to insult you, but when you bed the keybed, do you start with the glide bolts completely out of the picture? In other words, they are not protruding past the keyframe. Starting with that, turn the second from the right bolt first to where it just barely touches the keybed by knocking on the keys, and then barely turn the bolt a quarter turn. Then do the middle one, followed by the fourth, then the bass end and last the high treble.  

    Another thing to remember is that keydip is not that critical. Yes, it should be about 3/8, or 10 mm, but it's more important to have after touch, even if you have to remove a .005" punching.  A pianist is not going to feel a difference of .005". 

    Wim





  • 5.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-22-2024 16:52

    Yes Wim, that is exactly how I bed the action frame. I use Steve Brady's knocking technique that he writes about in his book, "Under the Lid." I start with all the bolts turned up and not touching the key bed. And I make sure it is bedded with dampers down, dampers up, and then with the shift pedal depressed with dampers down and up. 



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 6.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-22-2024 18:14

    Of course, even bedding first and then setting keydip next, that dip will not be accurate except in the keybed where the glides were set. But I'm with Wim: aftertouch is far more important than dip. A good pianist will notice 10 mil inconsistencies in aftertouch far faster than than in dip (10 mils being a far greater portion of a .045" aftertouch than a .415" dip). Given that, aftertouch does need to be done in the keybed (unless of course you have the Grandworks System).



    ------------------------------
    William Ballard RPT
    WBPS
    Saxtons River VT
    802-869-9107

    "Our lives contain a thousand springs
    and dies if one be gone
    Strange that a harp of a thousand strings
    should keep in tune so long."
    ...........Dr. Watts, "The Continental Harmony,1774
    ------------------------------



  • 7.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Posted 02-22-2024 18:21

    I understand the Yamaha approach to differ from what Wim is advocating, in that it assumes some protrusion of the glide beyond the surface of the keyframe at the outset.  I recall reading of it somewhere, probably on this forum.



    ------------------------------
    Floyd Gadd RPT
    Regina SK
    (306) 502-9103
    ------------------------------



  • 8.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-22-2024 20:34

    Joe, 

    Are saying that everything is wacked out simply by removing the action and putting it back in?  I feel like I'm missing something here. 

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 9.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-22-2024 21:10

    Peter went: "Joe, are saying that everything is wacked out simply by removing the action and putting it back in?"

    If it was true that simply sliding it out of and into the same piano, then it would matter whether the dip was done in the piano or on a nearby bench, or whether that bench was done on an everyday bench, an Edwards action caddy, or a Grandworks frame. You pull it out of the piano and what ever dip you may have already set will get messed up. What's really at issue is the flexibility of the keyframe.

    Joe went: "I have noticed that even the most minute change in the action caddy setting will change the key dip, which tells me that key dip is ultra-sensitive to any minute changes in bedding the action."

    There are many regulating steps which are only affected by bedding in a distant, minor way, and thus don't need a consistent bedding to get done. But dip (and aftertouch) ARE sensitive to minute changes in the bedding. To mitigate this sensitivity, the two bedding surfaces (keybed and regulation bench) have to match (or at be least be replicated). I don't believe that the Edwards caddy is designed to replicate the keybed.



    ------------------------------
    William Ballard RPT
    WBPS
    Saxtons River VT
    802-869-9107

    "Our lives contain a thousand springs
    and dies if one be gone
    Strange that a harp of a thousand strings
    should keep in tune so long."
    ...........Dr. Watts, "The Continental Harmony,1774
    ------------------------------



  • 10.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-23-2024 08:44

    The Edwards caddy doesn't span the entire keyframe, and the unsupported ends are subject to flexing. Also, the caddy only "beds" the balance rail and doesn't account for any crown in the front rail. 



    ------------------------------
    Mark Dierauf RPT
    Concord NH
    (603) 225-4652
    ------------------------------



  • 11.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-24-2024 15:04
    An article in the March 2023 Journal by Jim Ialeggio has a good description on grand regulating outside the piano. Lots of good info to chew on.

    Joe Wiencek




  • 12.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Posted 02-24-2024 10:32
    My approach, and perhaps this is already understood, is to bed the keyframe in the piano, set dip at least on samples, then do not change the keyframe or glides in the shop.
    Instead, shim or other wise change your work bench until you have re-created the dip set in the piano. For string ht I like sample let off set in the piano, then adjust let off rack to recreate.





  • 13.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-24-2024 13:09

    I also follow S. Fenton's approach. Bed the keyframe in the piano, set dip/aftertouch on section ends, then take the frame to the bench and shim until the aftertouch on the section ends matches what it was in the piano.



    ------------------------------
    Adam Schulte-Bukowinski, RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska at Lincoln
    ------------------------------



  • 14.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-24-2024 17:34

    You are absolutely right, Floyd. I learned this the hard way years ago. Yamaha's keyframes are quite flexible (and I believe this is the case with Samick too). If you bed them like a Steinway you will lose a significant amount of keydip and aftertouch. This needs to be mentioned frequently. 

    The protocol for keyframe bedding at the Shigeru Kawai Seminar was to regulate with the glides all the way up to be absolutely certain they weren't affecting the regulation. Their' recommendation was to set them at the very end of the regulation and verify that they are not affecting keydip. 

    Steinway, Kawai, and Baldwin I believe are all of the "stiff keyframe" variety.  



    ------------------------------
    Ryan Sowers RPT
    Olympia WA
    (360) 480-5648
    ------------------------------



  • 15.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Posted 02-24-2024 17:50
    Hi, Ryan,

    More examples of one size not fitting all.

    Steinway had keyframes that were more stiff until they adopted Klüge keyframes and keysets. Even then, the more early Klüge sets were more flexible than they became later. Further changes have come as they changed the forefinishing process as part of the convergence of the Hamburg and NY production standards; and to accommodate the design requirements of the Spirio system.

    Kind regards.

    Horace





      Original Message




  • 16.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-24-2024 17:59

    Hi, Joe -

    I have four grand regulating protocols, available on my website grandwork.tools for free. One of them outlines bedding the keyframe and another taking samples of bedding and strike and setting up to them on the bench. As Bill Ballard mentions in this discussion, I have fancy tools that can help as well. But these protocols can succeed with the tools and bench you already have, perhaps with the addition of Keysteps (this link shows you the entire Leveling-Sampling Kit, but you can purchase the minimum needed).

    The Keysteps provide a method of memorizing the shape of the keyframe in the piano and using a WNG Dip Tool for weighted kissing samples, the exact location of strike relative to it. When the keyframe shape is duplicated on the bench, the kissing samples will set up strike on the bench extremely accurately.

    The result is that the work you do on the bench fits back in the piano. Your dip can be whatever you need it to be and aftertouch can be set on the bench. If your bench, the bedding can be fine-adjusted by using front keypin punchings for back and front rails and glidebolts for balancerail. The glidebolts need to be reregulated in the piano, but this is easy using a WNG Bedding Tool.

    Please feel free to contact me with questions.

    Chris



    ------------------------------
    Christopher Brown
    chrisbrownrpt@gmail.com
    (978) 505-7728
    ------------------------------



  • 17.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-25-2024 13:43

    Joe -

      I sensed some basic confusion in your original  question and wondered how you might re-frame (NPI) it, after the numerous comments you received, but, while waiting, I had a few followup questions for you-

    • why would you be setting keydip out of the piano, on a caddy that can't possibly have the same controlled adjustability as something like Chris Brown's set up accomplishes?  (note: there HAD to be a reason he devoted so many brain cells to the project)
    • you say the key dip changes every time you re-bed the keyframe.  Others have already questioned this.  Of course key dip will change if you alter the bedding, but the question is: why are you 're' bedding, if your painstaking effort was successful to begin with.  I think your focus needs to remain with the reliablity of the bedding process and the applicability of that process to the given manufacturer.  As Horace Greeley further described, even within Steinway, the methods of construction have changed over time, requiring modifications in approach.
    • from my own experience (specific to Steinway), I'll share these marginally useful observations:
      • check shape of keybed with straight edge for any obvious anomalies
      • check underside of keyframe, front to back, along its entire length for the presence (or absence) of 'crown', which is part of Steinway design.  If the frame has collapsed (straight edge contacts balance rail wood) it will be impossible to reliably bed using the traditional 'tap' method, and will potentially create other problems such as excess shift friction
      • BACK  RAIL!!! I admit it. I dislike them.  I tend to avoid them, ususally to my detriment.  While this may be one of those steps that Bill Ballard referenced as not having a significant impact on keydip, the problems associated with poorly fit back rail can be subtle and persistent, especially if there is inadequate postive pressure from 'dogs' (or dags?).
      • To add to the confusion, I would re-pose a question to Horace (or anyone else who knows) that I think I asked some years ago: I thought I remember an 'old-timer' describing the intentional flexing of the frame with extra pressure from the glide adjustment to increase the stiffness of the frame, to reflect energy.  This would require that the dogs/dags exert positive contact to prevent the back rail from lifting, and not be excessive enough to create shift drag or squeaks.  Anyone know if I made this up?


    ------------------------------
    David Skolnik [RPT]
    Hastings-on-Hudson NY
    (917) 589-2625
    ------------------------------



  • 18.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-25-2024 17:09

    Sorry about the confusion my initial question caused. Here is a clarification.

    Here is my current protocol for bedding:

    1) I bed the action in the piano using the knock method with the side bocks tightened down. I make sure the action is bedded properly with sustain pedal up, then down, then with shift pedal activated while pressing up and down with the sustain pedal. So, I bed the action frame in four different positions. 1-Sustain disengaged, 2-Sustain pedal engaged, 3-Shift pedal engaged with sustain pedal disengaged, 4-Shift pedal engaged with sustain pedal disengaged.

    2) I then set key dip on sample keys up and down the keyboard while it is still in the piano.

    3) I take the action out of the piano and put it on the Edwards dolly. I do not touch the glide bolts, but use the Edwars dolly adjustments to match the exact key dip that was set in the piano for each of the sample notes I am regulating. Sometimes I will take the top action off in order to install a capstan boat to figure out how much it needs to be moved if that is a problem. Then I reinstall the top action.

    4) I then put the action back into the piano, install and screw down the side blocks and let it sit for a while. The problem is when I come back to the piano either later in the day or the next day, the bedding is off and needs to be reset. So, I reset the bedding to where it is good again and then check the dip and the dip has changed. This is the problem.

    All your comments have been helpful to think about this issue, and makes me think of the questions below: 

    ?- I do wonder if using the WNG bedding gauge instead of the knock bedding method would be a more accurate way of bedding the action.

    ?- I also wonder if on some pianos taking the action in and out of the piano can actually minutely shift the position of the wood joints that hold the action frame together. If this is the case then the bedding will always change when the action is removed and put back into the piano. The piano I am working on is from 1922, so I would not be surprised if the wooden key frame joints have deteriorated. A remedy for this would be to take apart the action frame on older pianos and reglue all the joints. This is something that I have never thought of before, but it might actually be something that would help with action frame stability on old pianos. Do some piano rebuilders do this? Take apart old action frames and reglue them before doing their action work? 



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 19.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-26-2024 00:56

    Hi Joe -

    Thanks for playing along.  I have a few more thoughts on your enumerated points:

    This comment strikes me as key -

    "The problem is when I come back to the piano either later in the day or the next day, the bedding is off and needs to be reset. So, I reset the bedding to where it is good again and then check the dip and the dip has changed. This is the problem."

    What do you mean, precisely, that "the bedding is off"?  Is it knocking?  Then, once you correct it, is the dip still incorrect?  By how much?  Does this happen all the time or only sometimes? It's possible to imagine that, with a 'lightly' bedded frame, changes in humidity can produce such symptoms.  Also, we didn't establish whether this happens with particular manufacturers or across brands.  

     A potential variable in the 'knock' method, even without the problem of a possible absence of keyframe crown that I previously mentioned, is the actual amount of pressure you chose to have being exerted by the glides.  We gauge this by assessing how much force we have to employ in lifting the action to induce the knock. 

    You thought about the possibility of the keyframe members having become unglued, which is worth checking at the outset, but most frames (I think) are secured with screws.  On the other hand, there's always potential for some effect when you disassemble and reassemble the top action from the frame.



    ------------------------------
    David Skolnik [RPT]
    Hastings-on-Hudson NY
    (917) 589-2625
    ------------------------------



  • 20.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-26-2024 09:21

    In addition to David's question(s) just how much has the dip spec changed in this scenario? 

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 21.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-26-2024 18:11

    Yes, David, when I say the bedding is off after putting the action back into the piano after having it on the Edwards Trolley, I mean that it is knocking. Then  after I re-bed the action the Dip has changed. I would have to keep better track of how much the Dip changes, but it is obvious when I feel it on the Dip Block. I would estimate the change to be around a .006 to .012, but I am not exactly sure. I will pay better attention to it and write down when this happens. 



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 22.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-28-2024 09:00

    Joe,

    Knocking everywhere? Or just one or two studs knocking ever so slightly? 

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 23.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-28-2024 09:32

    Peter, Slight knocking, usually on the first and second bolt from the left, bass side of the piano.

    Joe



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 24.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-28-2024 10:00

    Are all the stack screws absolutely tight?  Does the stack sit squarely on the feet of the keyframe?  Is the hammer rail straight when it's screwed down?   I suggest that the stack is influencing the flexing of the keyframe so that when you put it in and take it it's changing the bedding.



    ------------------------------
    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
    ------------------------------



  • 25.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 02-28-2024 10:10

    Hi Paul, Yes, all stack screws are tight. If any become loose I put West Systems epoxy in the hole and re-thread it to create a very tight screw fit. And yes, the stack feet are all sitting squarely on the frame. I am meticulous about these things. In addition, I always let the stack sit in the piano for hours or overnight after putting it back into the piano in order to let the action frame settle and adjust to the key bed. 

    What I am wondering is, are other techs having this same experience as I am having, or is it not an issue? Or do you all notice changes in the dip when you re-bed the action, but don't worry about it?



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 26.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-28-2024 12:35
    Something is strange.  Dip is certainly affected by changing the glide bolts.  Steinway factory even refers to them as touch regulating bolts.  But to keep changing after you alter the bolts' position, and that happens not through seasonal changes is indeed odd.  Are all the screws tight for the keybed to rim and belly joints?

    Joe Wiencek





  • 27.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-28-2024 16:53

    Joe,

    Actually no. Once the studs are set  they're set. I "rarely" have trouble after that. 

    Having said that, on a rare occasion I will notice the need to readjust one or two but it is ever so slight and quickly accomplished just on the offenders. If that adjustment affects any others I will make the correction, but it is extremely slight. 

    SOME keybeds are overactive (hyperactive) to humidity change. Years ago Scott Jones developed a screw on device to reinforce overactive highly flexible keybeds (so this a known issue), but he discontinued it due to lack of interest. 

    Interesting...

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 28.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-29-2024 11:14

    Couple of considerations to add:

    1. The return spring applies pressure, friction, and influence. It may not bear straight into the keyframe - check for indentations in the keyframe, check squareness to keybed. I take the spring out when regulating, sand / scrape flat the keyframe's treble side, and make sure the spring is shimmed vertical when it goes back in. Stiffness added to the sides of the keyframe (which are the stiffest parts anyway), coupled with friction, make fine setting of first and last glidebolts particularly hard and difficult to be sure they are not out of balance with their neighbors and thereby unstable. 

    2. Make sure cheekblocks don't over-bear on the keyframe guide pins. If they do, they will send vectors of influence back into the action, particularly but not exclusively into the frontrail. A corollary to this is to make sure the cheekblocks complete a crowned frontrail fit and that this fit is replicated in your bench setup.

    3. Beware the cantilevered backrail. With the frontrail held down and the default solution to a knock to bear further with that glidebolt, this is a hazard. Avoid it by making sure all glides are free of the keybed when you begin (accept the hidden studs in a flexible style keyframe - leave them in place). There may be a natural resistance to doing this because it appears to add time to the touchup, but if the backrail is cantilevered, you will never achieve a stable replication of action relationships on the bench... Corollary to this, make sure your backrail and frontrail fit before adjusting the balancerail.

    4. Check your bedding and adjust the balancerail with the action fully assembled. Key and hammer weights and fit of topstack to cleats are what they are and the keyframe will lack their influences when not there. Awkwardly, the backrail and frontrail are virtually impossible to bed with the action fully assembled. Check my keyframe bedding protocol for suggestions on how to integrate work to achieve these with a validated final result.

    5. Set balancerail without pedals for work on the bench - there are no pedals on the bench and sample replication is complicated enough. Then, reset with pedals back in the piano.

    6. Do use the glidebolts to set up on the bench (unless you have my tools). They are designed for this. You needed to fine adjust them in the piano to take meaningful samples for bench setup, but for those samples to work on the bench (which inevitably has a slightly different shape from the keybed), they must be changed as needed to accommodate the new shape. Then, touch them up back in the piano with pedals, and check your work when the spring has been reinstalled. 

    7. A couple of last thoughts. When the action is actually set up on the bench with in-piano relationships, you can adjust key level and dip there, and all other aspects of the regulation including aftertouch (no, not dampers, oh well). This implies that you could take fully regulated notes from the piano (with as-is key height) and use aftertouch to confirm bench setup. Or even take as-is regulation of selected notes, memorize their aftertouch, and note the same result when setup is complete.

    OK. Last thought. I promise. Check friction that might affect your samples and make sure sample hammershanks are not resting on their rest cushions before sampling. 

    Hope these help. Sound like a lot of complications, I know, but a thorough approach allows accurate bench regulating and that frees you from chasing your tail with instabilities undermining your efforts to get it right. If you are adamant to make everything right in the piano, working in sync with the elements, like chiseling with the grain or swimming with the current, will save you time and energy overall.



    ------------------------------
    Christopher Brown
    chrisbrownrpt@gmail.com
    (978) 505-7728
    ------------------------------



  • 29.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-29-2024 08:31

    Wheels do not sit directly centered under the legs.  Incorrect position of the wheels can cause the keybed to be torqued.

    People may scoff at this protocol, but I find it critical as a starting point:  the wheels need to be set so they are facing either to the front or the back.  This will alter the regulation.  If they are set facing either side of the piano the keybed will be torqued which in turn will change the regulation.  If the keybed is torqued, installing the action will further affect the torqued situation.



    ------------------------------
    Tim Coates RPT
    Sioux Falls SD
    ------------------------------



  • 30.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-29-2024 11:14

    Tim is right on the money.

    I was told years ago though that Bosendorfer recommends that the front casters be oriented pointing inwards, so that if there is going to be any flex in the bed, it would be to flex the middle upwards (theoretically always the same if oriented thusly). Other orientation would tend to be random (again assuming a flexible keybed).

    I try to follow the above rule. Some simple testing should prove whether you have an issue there or not.

    Peter Grey Piano Doctor 



    ------------------------------
    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 31.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 02-29-2024 13:57

    Wow. Thanks to all for their erudition. 

    Sure would be easier if everyone played the harmonica.



    ------------------------------
    Steven Rosenthal RPT
    Honolulu HI
    (808) 521-7129
    ------------------------------



  • 32.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Member
    Posted 03-05-2024 12:27

    Wow, I did not know that about setting the direction of the casters on each leg. Interesting!

    And thanks Chris Brown for taking the time to go into such detail. A lot to analyze there. I will reread what you wrote a number of times.



    ------------------------------
    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
    ------------------------------



  • 33.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 03-05-2024 20:34

    Joe went: "Wow, I did not know that about setting the direction of the casters on each leg. Interesting!"

    It's always interesting to put a number on it, with straight-edges or dial indicators. (This one is easy to remedy: keep the bass and treble casters in the direction of moving forward.) You could take a piano which has rolled around all day on stage and then  stop it at somewhere on the stage and measure its flatness with a straight edge. Then rotate these casters 90º away from or back towards each other, and measure again.

    I was curious about how much the sustain pedal pulls downwards on the middle of the keybed. A dial indicator read 7mils (.007"): the thickness of ordinary white paper. So I figure I'll put in 12 mils (from nothing) at the glides, which I don't think is a serious deflection/imposition. Sure, it's a fluid situation, but at least it's something I can be consistent with.



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    William Ballard RPT
    WBPS
    Saxtons River VT
    802-869-9107

    "Our lives contain a thousand springs
    and dies if one be gone
    Strange that a harp of a thousand strings
    should keep in tune so long."
    ...........Dr. Watts, "The Continental Harmony,1774
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  • 34.  RE: Does anyone have a protocol for bedding the action so that key dip remains accurate?

    Registered Piano Technician
    Posted 03-06-2024 11:16

    Joe,

    After I bed the frame (essentially as you initially described in your OP), if later I find any discrepancies, I simply correct those showing (extremely slight turn of the stud(s), check the rest and move on. I will not start again from scratch. I chalk it up to: "hey, stuff happens", fix and go. That's my MO.

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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