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Letoff/Drop regulation

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  • 1.  Letoff/Drop regulation

    Member
    Posted 10 days ago
    I have seen different people say that they regulate a grand action so that the toe of the jack touches the regulating button at the same time that the drop screw contacts the repetition lever (or balancer).

    Two questions:

    1. How does one test to know that this is happening while regulating?
    2. What is the change in feel to the action if this does or does not happen?

    ------------------------------
    Rex Roseman
    Akron OH
    330-289-2948
    ------------------------------


  • 2.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 10 days ago
    We do that by the amount of drop. The acceptable distance is 1/16" below let off.

    We call it the drop screw, but technically it should be called: "the screw that starts pushing down the balancier at the exact moment the jack touches the let off button".

    ------------------------------
    Willem "Wim" Blees, RPT
    St. Augustine, FL 32095
    Tnrwim@aol.com
    ------------------------------



  • 3.  RE: Letoff/Drop regulation

    Member
    Posted 10 days ago
    Wim

    Thank you. That is what I have been doing. I just didn't realize what was happening in those terms. Thank you for the clarification.

    ------------------------------
    Rex Roseman
    Akron OH
    330-289-2948
    ------------------------------



  • 4.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 10 days ago
    Well, Wim's nomenclature really only describes its own motion, disconnected from the motion it transfers to other parts. It is connected, The drop screw is what serves as the resting point the hammer will descend to during aftertouch. That point is fixed at the drop screw by the rep spring underneath it and the only other way the knuckle-balancier contact can change is if the capstan changes its lift under the wippen body.

    So , it's the "drop screw" because it determines the maximum drop the hammer is allowed. The hammer has to drop below LO, but the "fatter" drop is, the worse deep-repetition gets.

    ------------------------------
    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
    +++++++++++++++++++++
    ------------------------------



  • 5.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 10 days ago
    1.) It's best seen on the bench. Keep your eye simultaneously on the top of the jack and the back of the rep lever. Each of these will signal their respective motion, when they contact their adjusting button.

    2.) Both the jack and the rep lever will be pushing against the butterfly spring (the jack at the LO button, and the latter, the drip screw). If they hit at the same time, this make the escapement crisper. If they don't, the escapement will seem softer or out-of-focus, depending on how the pianist likes escapement to feel.

    This simultaneity isn't always possible, even on a piano whose designers intended it, kind of like jack-knuckle alignment in which the knuckle mouldng and the back of the jack is supposed to form a straight line, but many times doesn't.

    ------------------------------
    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
    +++++++++++++++++++++
    ------------------------------



  • 6.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 10 days ago
    Like William Ballard said.  Lift the hammers up out of the road to see what is going on.  As you lift the back of the key, or push on the back check, the top of the jack should not begin to move horizontally before the repetition lever surface contacts the drop screw.  On the other hand, horizontal movement of the jack should be immediate, and not delayed, in relation to repetition surface/drop screw contact.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 7.  RE: Letoff/Drop regulation
    Best Answer

    Posted 10 days ago
    Look up the video "You Don't Know Jack" by Nathan Mills on FB or Youtube. Regulate let-off, then put the action on a table or workbench, stand on the backcheck side, lift all the hammers forward away from the stack, individually lift 1 key and look at jack, if the jack tender rises then moves forward then the drop screw is too low (too much drop), turn it counterclockwise to raise it up.

    If jack tender moves forward then starts rising up then the drop screw is too high (not enough drop which would have made it difficult or impossible to adjust let-off beforehand), turn it clockwise to raise it up.

    You want to see 1 motion from the jack tender, not two (not up and forward, or not forward and up).

    Of course if you are having a hard time seeing this asjust drop way low on one note and then you'll see jack tenser rise high up before moving forward when you test it.

    I'm not sure how it feels, maybe try this test so you can see for yourself: adjust 10 consecutive notes' drop a tad lower than usual (maybe ¼" hammer drop), adjust 10 so that toe and rep lever hit button and screw simultaneously, and adjust 10 so that drop is a tad higher than usual (make it the same distance away from string as let-off...so, no hammer drop at all). Then play each group of 10 and see for yourself how it feels.

    ------------------------------
    Cobrun Sells
    cobrun94@yahoo.com
    ------------------------------



  • 8.  RE: Letoff/Drop regulation

    Member
    Posted 10 days ago
    As with all regulation there is a circle of refinement. to really set the height of the Repetition Lever Upstop Screw, the action needs to be fully 'regulated'. To set an even height, the key dip/after touch needs to be set. After the Let Off has been adjusted, you can time the Upstop Screw by lifting the end of the jack to touch the button.
    Adjust the Upstop Screw to contact the Repetition Lever when the jack toe touches the button. Confirm by lifting the rep lever to touch the screw and see if you can move the jack higher. Another method is to lift the jack to the button and you'll notice slight motion (or not) at the back end of the rep lever. Then notice the distance the hammer resides from your Let Off Guide at full key dip. Set an equal space below the L/O line for the section.  The TLRG (Pianotek pg. D-13) is a great tool, I use it exclusively :-)

    Having the two contact simultaneously develops a cleaner, crisper after touch with their respective springs engaging same-ole-timeously.

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

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



  • 9.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 7 days ago
    I'm sitting here with my head in a piano asking myself if the ideal is always possible.

    The piano is a 1988 Young Chang G-157.  Knuckles are newer than everything else in the action, replaced maybe 6 years ago, not badly worn.  Let-off is close enough that I can play off of the jacks, but not so close that the hammer interferes with the motion of the string when sounding loudly. Drop is minimal.  I'm looking in particular right now at the top note of the overstrung section.

    The surface of the repetition lever touches the drop screw, and the repetition spring begins to compress.  The jack does not immediately deflect horizontally--it rises slightly first.  I see three options.  I can raise the drop screw, but drop is already minimal.  I would need to eliminate it altogether.  I can lower the regulating button, but I kind of like being able to play off of the jack.  I can allow the jack to be at rest further under the knuckle, but it is already aligned appropriately with the core, and I don't want to increase the friction of the jack scrubbing on the bottom of the knuckle.  There's enough of that already.  Yes, I know I can teflon the knuckle, but not everybody is willing to do that.

    If the ideal is not possible in this situation, then I have a question I'm trying to figure out:  What exactly is it in the design of an action that either enables or prevents this degree of precision in the timing of the regulation?

    Or am I missing something obvious?

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 10.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    Floyd

    This is what I learned from Eric Schandall at Steinway. With all the other adjustments made, stand at the back of the action, (or turn the action around), and lift the hammer out of the way. Slowly push down on the key. The top of the jack should move towards you, (away from the front of the piano) at the same time it rises. If it rises first, before moving forward, lower the drop screw. It should take less than half a turn to get the jack to move forward and up at the same time.  I'm not a player by a long shot, but when I did that to an action, and played the piano, it felt more "solid".

    ------------------------------
    Willem "Wim" Blees, RPT
    St. Augustine, FL 32095
    Tnrwim@aol.com
    ------------------------------



  • 11.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    Wim, if it rises first, lowering the drop screw will exacerbate the problem, not resolve it.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 12.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    I'm sorry, it's been a while since I've regulated a grand action, and I'm trying to visualize what I'm supposed to do sitting in my Lazy Boy.
    Obviously, I got it wrong, so do the opposite.

    ------------------------------
    Willem "Wim" Blees, RPT
    St. Augustine, FL 32095
    Tnrwim@aol.com
    ------------------------------



  • 13.  RE: Letoff/Drop regulation

    Posted 6 days ago
    I'm gonna have to join Floyd on this question. Anyone? How is an action designed so that one could or could not get simultaneous contact of the drop screw and jack toe?

    Also, how close can we/should we get drop to let-off? I know we don't want a hammer bobbling on the string if it pops out of check and the repetition springs pushes the repetition lever/hammer back up to the string. But if simultaneous escapement (rep lever and drop screw/jack toe and let-off button) happens and let-off and drop are the same distance from the string but there is no bobbling from the drop being too high then is that a bad thing to leave drop that high?






  • 14.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    I suppose maybe it boils down to parts wear.  The hammers in the action I am looking at have been filed, such that the bore distance is now less that what was original.  I noted above that increasing let-off would resolve my problem, but that I was unwilling to sacrifice the ability to play off of the jack (a phenomenon referred to in another thread as ghosting the tone.)  If my bore distance was longer, the "compromised" let-off distance would not be compromised at all.

    I usually find that the issue in trying to coordinate the bump is in the direction I have described above -- the jack rises before it begins to move horizontally.  So I propose that a key element of design that enables or prevents coordination of the bumps is bore distance, and that most of the problems I run into are not, in fact, design problems, but rather a consequence of hammer wear.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 15.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    Floyd Gadd went: "the jack rises before it begins to move horizontally."

    We probably need to be clear about what's happening. The jack isn't rising; it's the rep lever which begins to lower as soon as it contacts the drop screw. (Kind of like, does the spring-driven rep lever throw the hammer upwards during actual play (the way we see it while setting rep spring strength)? No, quite the opposite, it throws the rep body and the key downwards.)

    To recap, 1.) when the jack  tender hits the LO button, it moves forward (towards the keyboard) and 2.) when the rep lever hits the drop screw, it moves downwards



    ------------------------------
    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
    +++++++++++++++++++++
    ------------------------------



  • 16.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago

     

    Can you reduce keydip/aftertouch at all? That would allow you to raise the drop screw.






  • 17.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    The issue here is that drop is already so minimal, that raising the drop screw would eliminate it altogether. Cobrun has raised the question as to whether this is in fact an option.  I think your point, Mark, is pertinent to his question, but otherwise, keydip and aftertouch operate independently from this coordination of the bump.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 18.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    With less dip, the hammer will "drop" more after escapement, which will allow you to raise the drop screw.

    I like to have the hammer drop slightly but positively below let-off. I've also backed off setting let-off as close, but not so much that I can't still play off the jacks.

    ------------------------------
    Mark Dierauf
    Concord NH
    603-225-4652
    ------------------------------



  • 19.  RE: Letoff/Drop regulation

    Member
    Posted 6 days ago
    The jack does protrude above the rep lever thru escapement. That's the way it works. I have never seen it not do that.

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

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



  • 20.  RE: Letoff/Drop regulation

    Member
    Posted 6 days ago
    Re simultaneous escapement, this is an adjustment where, an action, even if it designed perfectly, will still feel awful, mushy and hard to predict , until the two are timed to a single crisp bump.

    The problem often comes, as is being mentioned, what do you do, when simultaneous escapement is just right, but it leaves drop too high. Drop too high meaning, either, there is no feeling of letoff anymore, or when pressing the key into the front punching, it blocks the string (will result in a double strike)?

    Many actions because of the parts design and relationships, will not allow a super high letoff, ie the kind of high letoff folks teach concert regulation requires.  In this case, you must lower letoff a tad. The geometry will not allow letoff to be that high and still achieve simultaneous escapement. One proves simultaneuos escapement and letoff height on a sample key or keys, before setting letoff.

    The double escapement is so important,  it takes precedence over super high letoff. Like Mark, I have backed off my letoff height, both in response to most actions asking me to lower letoff a tad as described above, and also, because very, very, very few actions receive concert level attention to regulation changes...lets be real...

    The other thing is, that with hammer weights that are not off the deep end, super close letoff is not necessary. This means super high letoff becomes  superfluously problematic. My letoff is 2mm these days, maybe 1.5mm if I know the action will be looked after regularly, like a good recording studio.

    The other problem with super high drop, is it will kill checking dead. Checking depends on getting the rep lever and its nasty little spring, out of the checking picture in time for checking to occur. PPP checking can be difficult, because the stroke happens so slowly, relative to a mf or f blow, that hammer rebound happens, before the rep spring has been compressed, thus failing to get the rep lever out of checking's way.


    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 21.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    Thanks Jim.  You're helping me evaluate my priorities.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 22.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 5 days ago
    I might be bending this thread away from its original question, but...
    In staring at my action model I see the knuckle rotating quite a bit during hammer/shank motion.  The set-in-stone rule of jack lined up with the back of the knuckle core seems to make sense with the hammer in its lower, rest position, where the jack is centered in line with the apparent direction of force, but as soon as the hammer begins to move the knuckle rotates and the center of force of the jack is not necessarily in line with the center of the jack.
    There are admonitions to properly position the jack to prevent excessive wear or to prevent too easy or too hard escapement and excess wear.
    Who has experimented with deeper jack positioning (1/2 mm or less)?
    How do you sense the changes in playing and feel?  How  do you think it affects the issue of drop regulation and drop screw vs let-off button contact?

    ------------------------------
    Blaine Hebert
    Duarte CA
    626-795-5170
    ------------------------------



  • 23.  RE: Letoff/Drop regulation

    Posted yesterday
    Blaine, I just thought about this too. And although the knuckle is sliding back further towards the inside of the piano I would venture to say that the force from the jack is still angled at near the center of the knuckle (although not in direct alignment with where the knuckle attaches to the shank by the stem). I think I saw somewhere in Igrec's Pianos Inside Out that there are 2 types of frictions going on at the contact between the jack/rep lever and knuckle. There is the physical contact and friction between the jack/knuckle and the contact and friction between the rep lever/knuckle. But then there is also the friction of motion in that wippen is rotating on its flange and the hammer is rotating on its flange. At key rest both angles of the wippen and hammer are slightly off in that when they start traveling at the beginning of a keystroke they are not moving parallel to each other at the jack/rep lever/knuckle contact point.

    But, as the hammer nears the string the jack/rep lever/knuckle are at their closest to traveling parallel to each other allowing for greatest transfer of force from jack to knuckle with less force being lost due to non parallel travel and less motion friction.

    But also, Mike Reiter in his Relentless Repetition class mentions that during a hard blow the jack will actually follow the knuckle backwards a little bit towards the inside of the piano (towards the hammer) before the static friction between the top of the jack and knuckle release and the knuckle continues sliding backwards as the jack repositions itself before being tripped by the let-off button.

    So, as far setting the jack deeper? I don't think it would be useful.

    ------------------------------
    Cobrun Sells
    cobrun94@yahoo.com
    ------------------------------



  • 24.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 6 days ago
    Mark, when I am setting/measuring drop, I am not pressing the key to full dip.  I am only moving it far enough that the drop of the hammer can be observed.  I do recognize that the amount of dip/aftertouch will determine how much closer the hammer moves toward the string with the key fully depressed, and that that is an important consideration in terms of performance, but in the terms of reference I am using, drop is not defined at end of key stroke.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 25.  RE: Letoff/Drop regulation

    Member
    Posted 5 days ago
    Its interesting that folks look for secondary evidence of where drop is adjusted, always after letoff or at the end of the stroke.

    I don't do this. I only take the key to the point where the synchronicity is felt, ie, just to the point where the  jack tender touches the letoff button, and where the re lever touches the drop screw. Since this is what the pianist will experience, I work to the feeling of synchronicity at the pianist's end of the key.I work the key, from the pianist's position, approaching that point, with wrist resting on non-played keys, played with a finger, bringing the action to that point repeatedly at about mf speed.  I don't go through letoff, but just to the point where the finger feels synchronicity.

    In this way, drop/synchronicity, can be tested and adjusted, outside of the piano, regardless of whether dip has been duplicated or not. In the rise of the hammer technique, on the other hand, the hammer rise represents secondary evidence, and requires that dip has been accurately reproduced, which is a pain, without the right setup.

    In my own case, since I have a dip duplicating table with string height gantry, the action is on the dip table, dip is already duplicated, and I have the string height gantry in place. So I know where string is. After I find the synchronous point, before letoff, which does not depend on dip, I check, at full dip, with punching compressed, that the hammer is safe from blocking the string. I do both the synchronicity test and the final hammer-not-blocking-the-string test on each note, as I progress. In this way, I can see, after one or two notes, ie, before I've gotten through 75 notes, whether I have gotten letoff right for this action, and can safely proceed to set drop as high as geometrically practicable.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 26.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 5 days ago
    How are letoff and drop felt by the pianist?  Is the feeling of drop anything other than synchronicity, the absence of gross movement of the hammer after letoff, and the presence of checking due to the clearance created?  Is the feeling of correct letoff anything more than absence of interference between hammer and string, consistent key dip and aftertouch, and thus a consistent length of power stroke as experienced at the front of the key?  How much does the ability to play a consistent pianissimo depend on some particular proximity of letoff to the string?  If you achieve everything else, but have a variability of even a couple of millimeters in letoff across the scale, what has been lost?

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 27.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 5 days ago
    I guess another dimension of the feeling of letoff for the pianist is the tactile sensation of the surface of the jack dragging across the knuckle.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 28.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 4 days ago
    The bump of LO tell the pianist that any further pressing on the key is wasted, and their fingers should be thinking about the next notes to be played.

    ------------------------------
    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
    +++++++++++++++++++++
    ------------------------------



  • 29.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 4 days ago
    There might be more to this than just good lubrication.

    At a recent NAMM show Steinway has a  "special" B on display.  Aside from having an unusual piant job when I played it I was startled at the touch; they had lubricated it to the point that it felt like an electric keyboard (interesting that no one else I talked to noticed)!

    I have not experimented with using a toothbrush or wire brush to rough up the knuckles but creating a controlled surface for the jack to move on shounds intriguing.

    Perhaps there is more to the feel of a new piano than we admit.

    ------------------------------
    Blaine Hebert
    Duarte CA
    626-795-5170
    ------------------------------



  • 30.  RE: Letoff/Drop regulation

    Member
    Posted 4 days ago
    whoowee...down boy...them is a lot of questions...

    For me, the feel of letoff, defines the action. The feel means, you want a clear sense that letoff is happening, but you do not want it to be a wall of friction, and do not want it to be an event of long duration. High drop reduces letoff friction. Really high drop makes the sensation of letoff go away entirely. So, as you gradually raise drop, you also gradually reduce letoff friction.

    Heavy hammers, accentuate the friction in letoff, and extend the letoff event (not beneficial in my view). The heavier the hammers get, the higher letoff has to go, in order to get drop as high as possible, so letoff is not a wall of friction. Its all connected, hammer weight, leverage, letoff distance from the string, drop, letoff friction.

    My take is that drop is more than synchronicity. As I just described above, it is also about letoff friction. Synchronicity creates a very clear initiation of the letoff event, and the shortest letoff event that action is capable of...they both are about the sensation of letoff, one about friction the other about clarity and duration of the event. The two define the feel of letoff, which defines the feel of the action to a great extent.

    Ability to play consistent pianissimo is relative to the leverage of the action and weight of the hammers. The heavier they get, the closer to the strings letoff needs to be, and the higher drop needs to be, to control letoff friction. These actions push the limits of the system to the max, and are high maintenance. Reasonably weight hammers, and slightly elevated leverage, allow letoff to be lower, drop to be lower, and maintenance to be lower. They both help ppp playing, but the systems behave differently. So, there is, in my view, no single answer to the ppp part of your question. Just to be aware of the weight/leverage aspect of the action you are working on, and work to that action's requirements.

    Consistency across the keyboard is felt as an intuitive connection to the action. A couple of millimeters in letoff, is miles. Keeping in mind when letoff is that inconsistent, the letoff friction will vary, etc etc etc. When the action lacks consistency, the player's mind has to process insane amounts of data for each and every key. When there is consistency the brain has much less data to decode regarding the machinery of the action. Consistency means that there is more brain space available to the player to musically navigate the music instead of spending all its resources trying to out guess the action's recalcitrant machinery.






    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 31.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 4 days ago
    I was baiting you, Jim :-)

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------



  • 32.  RE: Letoff/Drop regulation

    Registered Piano Technician
    Posted 4 days ago
    Thank you for taking the time to craft this answer. I'm going to need to study it for a while.

    ------------------------------
    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------