The following posts on hammer technique come from a very long thread on Pianotech in early 2014, entitled “What’s the Secret to going faster” (Somebody posed that question, and the thread evolved into use of an ETD and hammer technique). From that thread, I have selected mostly posts by David Love and myself, describing what we do in great detail – we are pretty much in agreement. The full thread is at http://my.ptg.org/communities/community-home/digestviewer/viewthread?GroupId=43&MID=634052&CommunityKey=6265a40b-9fd2-4152-a628-bd7c7d770cbf&tab=digestviewer - bm104
There was a shorter follow-up thread at http://my.ptg.org/communities/community-home/digestviewer/viewthread?GroupId=43&MID=634268&CommunityKey=6265a40b-9fd2-4152-a628-bd7c7d770cbf&tab=digestviewer - bm8 entitled “hammer technique.
Speed comes from efficiency. Efficiency means eliminating all that is extraneous and/or doesn't contribute to getting to the goal. That includes listening only as far into the tonal envelope as is necessary, which might be different when tuning a unison than when tuning, say, a fifth. (ETDs eliminate this disparity, btw, as interval checking is basically no longer a part of the tuning process except for, perhaps, a quick verification.) It also means eliminating unnecessary pin movements and reducing the number of pushes and pulls to get to your target. So hammer technique does matter. Hammer technique also contributes to stability because what is happening with the string is felt through the interaction between the hammer and the tuning pin.
How far to listen into the envelope is really just a matter of focus and eliminating the habit of hanging onto a note for too long. Hammer technique takes practice but the right kind of practice. It's not a matter of being faster or more frenetic in your movements, it's a matter of making fewer of them. The beginning tuner overcorrects and/or undercorrects. More experienced tuners develop a more precise feel for the relationship between pitch correction and pin movement. That's the goal. It makes the tuning not only faster but less physically stressful as well.
David Love RPT
ETDs can be a very valuable teaching aid to show you how to tune more directly to the target pitch. Less skilled tuners tune a little high, a little low, a little less high, a little less low, a little less high still, a little less low and on and on until they finally settle at the target.
More skilled tuners get to the target quickly and with fewer moves. The ETD can be useful for this type of training because it gives you instant and visual feedback as it relates to pin torque, actual pin movement, false movement and stability. It's this very refined and subtle control over the pin, along with learning to recognize quickly where you are aurally, that really creates efficiency and with that will come speed. Of course you can do that with the right kind of focussed practice without an ETD but a visual input can be very helpful--read more efficient.
Remember it's not just 10,000 hours, it's how you practice during those 10,000 hours. Practice doesn't make perfect, it just makes permanent.
David Love RPT
Here's a simple drill you can do with an ETD followed by an aural exercise.
On a grand piano pick a single string (mid range tenor is a good place to start) and tune it with the ETD so that the spinner, lights, whatever it uses stops.
- First place the tuning hammer on the tuning pin in the 1:30 position (the hammer pointing away from you would be the 12:00 position). Now gently press down on the handle so that it gently flexes the tuning pin straight down toward the strings. Notice that the spinner moves in the flat direction as you flex the pin toward the string). Let go and notice that the pitch slowly returns to where you started.
- Second, with the tuning hammer in the same position gently pull the handle toward you on a horizontal axis without actually turning the pin in the block. Don't push the handle up or down, just pull it toward you with the force directed on a pure horizontal axis. Notice that as you flex the pin in this direction the pitch goes sharp as the pin flexes away from the strings and when you let go of the handle it should return to where you started.
- Now combine these two movements and find a place such that the downward toward the string pressure and the horizontal, toward you pressure on the pin offset each other perfectly and the spinner stays absolutely stationary. Let go of the handle and the spinner should stay exactly where it was. Practice this a few times to get a sense of how much downward pressure is required to be combined with the horizontal pulling of the pin to keep the spinner stationary without the pin actually moving in the block. Don't overdo it.
- Now, while watching the spinner, find the point at which you need to increase the twisting motion while simultaneously offsetting with pressing motion such that you can feel the pin move in the block and the spinner moves to the sharp side along with it. Focus on feeling the pin move. Try to do this with the smallest incremental movements possible. When you let go of the handle the spinner should stay exactly where it was.
You can do the same drill on an upright. The hammer should also be in the 1:30 position. The pressing of the handle will be away from you as in the grand and will push the pitch sharp rather than flat. Pulling the handle in a pure rotational motion (downward) will tend to flex the pin down toward the string and push the pitch to the flat side. Work with offsetting these two forces the same as in the grand and then getting the smallest incremental movement of the pin and an accompanying movement in pitch. When released, the pitch should remain where it was.
After you have some sense of that tune two strings in unison starting from degrees of displacement: 1 cent, 5 cents, 10 cents. Focus on the amount of movement you feel in the block and how much pitch change is associated with that. Do this exercise aurally. Try to tune directly to the pitch.
After that try and tune so that you hear the slightest swell to the sharp side of the note being tuned and then settle it into place with a very slight amount of back pressure. The back pressure required should not be enough to actually turn the pin in the block, but just to put it in a state where it will be just fractionally flexed toward the string and held in stasis by the string tension itself.
David Love RPT
What David Love has described is essentially the same method I use. Nice description of an exercise to learn that method, David! The benefits of the method are efficiency and solidity, accomplished at the same time. The pin AND string are moved the bare minimum, and you know where they are at all times. It is not an easy method to learn, but it pays benefits down the road that make it worth every bit of effort you expended.
A few additional details: The tuning hammer matters a lot, specifically how stiff it is, how little spring and flex is built into its design and construction. When there is spring and flex in the hammer, that springy element acts as stored energy, and shoots the pin past the target as you get close. This is particularly noticeable as you hone in on precise clean unisons. There are quite a few options out there for hammers. I like Fujan myself, but I'm sure many others work well. What does not work well is the design where the tuning head screws to the shaft, the shaft having a fairly small threaded end, and the threads are the main interface between the head and the shaft. The Jahn design where the head and shaft are one piece with ample bracing is one that works well. Nate Reyburn came up with a system where two surfaces lock together well. The Levitan hammer Pianotek sells (the cheaper one) seems to be well-designed. There are others, but you get the idea.
David's scenario is only one of a number of possibilities. In his scenario, There is low friction at the bearing points (string to capo and over the underfelt, or whatever the string needs to cross from the termination to the pin) and there is moderate torque/friction of the pin in the block. Since there is not much friction at the bearing point, leaning the pin toward the speaking length makes the pitch lower, but if there is significant friction, there might be no pitch change when you flex the pin. Similarly, if there is low friction between the pin and the block, there might not be enough twist of the pin before it moves to result in a pitch change.
So the problem is one of analyzing that particular string and tuning pin for the two frictional elements, and adapting your technique accordingly. If there is a lot of bearing friction, it might be necessary to flex the tuning pin away from the speaking length (pull up on a grand, push in on an upright) to get pitch to move in sync with pin movement, as one example. Sometimes the two frictional elements are really nicely balanced, and you don't need to do anything other than turn the pin, and the pitch starts to move just as the pin begins to move in the block. And sometimes you can get a nice mating of twist and friction by adjusting the angle of the hammer, say from 1 o'clock to 3 o'clock.
But it can be pretty confusing, and you have to be on you toes, not just going through a set of learned physical behaviors. Pins and strings on the same piano can vary a lot, and the one that sticks out as different is likely to be the one where the unison consistently goes out after you tune it. How would I know that? If you are paying attention, you will pick that sort of thing out. If you are going on automatic pilot, you are likely to miss it.
The bottom line in all this is that to go faster you need to be more efficient and eliminate unnecessary steps. Efficiency comes from getting to the target quickly but not just that, it also involves being able to leave the target quickly. Time is taken up not just by the less skilled hammer technique that doesn't get you where you are going quickly, but the time taken waiting around to make sure that the pitch is going to stay there. Better and more confident hammer technique not only gets you there faster but allows you to leave faster. Of course unstable pin setting of the pitch will require that you go back and retune that note again and, perhaps, any other notes that used that as a reference. More wasted time.
The elimination of unnecessary steps is also important. This can be something as simple as how you use mutes or whether you strip mute the piano. But all things being equal the aural tuning will always be slower than the etd tuning. The aural tuner simply has more steps. Most of those steps that the ETD user eliminates are the aural checks involved and adjustments made when the aural check reveals more refinement is necessary. The ETD user doesn't have that. Aural checks, if any, are cursory and quick. If the aural tuner is doing a thorough job of it, then aural checks exist in abundance through the temperament and octave setting. More steps equals more time. Of course the aural tuner can skip the aural checks but that will on average produce a less accurate tuning.
I've made my case previously about the speed advantages of ETDs in the pitch correction process. It is more accurate (given proper calibration or programming of the device) and virtually eliminates second pitch corrections in advance of fine tuning. Final passes will on average come from a point closer to the final target with only a single pass. This creates greater stability and a more accurate fine tuning eliminating the need for further corrections or "clean-up". I stand by that assertion.
ETD users do have to develop a second set of skills, namely hand-eye coordination to go along with the hand-ear coordination. However, I consider that a benefit since the shifting back and forth between modes (hand ear still required for unisons generally) helps to eliminate fatigue.
Finally, the ETD can direct you more quickly on problem notes where pitch recognition is difficult for various reasons or in more challenging areas, such as high treble unison tuning and stability.
So if speed or continuity in tuning times for every piano is the goal, along with developing precise hammer technique, an ETD will be a benefit.
David Love RPT
[Much intervening argument]
I'm not sure if I really want to jump into this, but I will anyway , with the idea that maybe I can contribute a wee bit. With respect to the video link Ed Sutton posted (made clickable here), and that some have commented on, I certainly agree it is too "fast and sloppy" for my taste - not sloppy per se, but I have no idea how clean or stable those unisons are, and neither does the tuner as far as I can see. But that was a VERY fast tuning, 3:20 for 48 strings, or an average of 4 seconds a string. That would work out to something like a 15 minute complete tuning, if you spent that much time on each string of a whole piano. So if your style calls for a quick setting of pitch, followed by refinement, especially of the unisons, then the technique is probably fine for the first pass.
The question of doubts as to quality, with respect to what David Love has described: I tune essentially the same as David, going by his description, and also agree essentially with everything he has written in this thread. Well thought out, well presented, solid stuff. I thought briefly of doing a short video, but then I realized that the convenient way to do that would be to use the same devise I use to tune to take the video - that doesn't work too well. I'd have to bring in something else with decent enough sound quality to be worthwhile (my video cam with a decent mike), and jump through a few hoops to create a format of video to share. Sorry, too much work. I will, however, assert for what it's worth that David's claims are entirely in line with my experience. I also, like David, tune for several concert venues and finicky customers, have for years (including 27 years and counting in a music department). I'm not much of one for blowing my own horn, but I think I have a pretty solid reputation based on the quality I have delivered over the past 30 odd years. And I often tune a concert level tuning, where all strings have to be moved, within 45 minutes. And it is concert quality. And it holds. I know because I follow myself, next day, next week, a couple weeks later, etc. There is no guess work here, I know for a fact that my tunings are solid (with the caveat that there are always a few exceptions I can't really explain - I don't claim perfection, just a high level). And my unisons are crystal clear - some of them may become a little "fuzzy" after a day of concerto competition, but nothing that stands out.
How can I tune that efficiently at that level? Precisely for the reasons David has been trying to get through: I already have the tuning set up in the ETD memory. All I am doing is tuning unisons. Hence, every bit of my effort goes to getting each and every single string to a set target, within very fine parameters, and making sure it will stay there. Yes, I listen and check intervals (6/4 chords in the mid range, octaves in the higher areas), and once in a while I catch something (usually a drifting string, or perhaps I carelessly brushed the screen and set the device octave up or down by accident), but it is just confirmation, not making decisions based on listening to a number of test intervals. I know from long, long experience that I CAN listen to all those intervals, and I will find that they are all where I decided I wanted them (when I made my own modifications to the tuning calculated by RCT, almost entirely consisting of raising the pitch of the top two octave by a small amount increasing to a somewhat larger amount: IOW I want a bit more stretch up there in keeping with my own taste).
Conversations about aural vs ETD remind me of having the same kind of conversation between woodworkers who use power tools versus those who don't. Yes, you can get very good results using only hand tools (planes, chisels, handsaws), but a router, for instance, once you know how to use it, will both speed up a number of tasks AND make it possible to achieve high levels of precision. As will using a straightedge as opposed to eyeballing a straight line, which is probably a better analogy. It still takes skill and knowledge to do the work, but the "advanced tool" makes for a potential of higher quality and more efficiency. That's all we're talking about here, using a tool to assist us in getting a job done, and done well. For some, it seems like we are talking about the fundamental principles of life, bedrock deeply held quasi-religious beliefs. Hey, live and let live. If that's what you believe, and it makes you happy, do it. Same thing if it is more pleasant to do without the machine.
I guess I will also add that many who write based on some small amount of experience using an ETD are really far too inexperienced to have the right to a solid opinion. It takes work to learn to use an ETD, any of them. Adjusting to a visual display, making muscle moves in response to visual cues, learning to interpret when the display is "jumpy," learning how to use the devise to generate a tuning that meets your own standards and tastes, etc., are a matter of a fair investment of time. Some people are pretty fast picking it up, others are very slow. Until you have learned the skills involved, you really can't judge how efficient the ETD might make you, nor can you judge the quality of results possible. It is very possible to tune very badly, and painfully slowly, using an ETD. Tuning continues to be a high level skill whether you use one or not. ETDs do not tune pianos. People do. The results depend more on the people and their skills.
[Intermediate posting of a video of tuning by John Formsma]
First, thank you for posting that. I appreciate you making that effort and putting it out there.
Since we both tune unisons aurally I think I can comment. Your method differs from mine in one major way. What I hear is a consistent flexing of the pin to move the pitch above the target and then a settling back. If the pitch doesn't settle back with the unflexing of the pin to where you want it then you start the process again either by pushing it down or pulling it back up always with a fairly large move (relatively speaking for my goal) above the pitch followed by a settling back down. If the pitch is above the target then you push it down below the target, flex the pin to move the pitch above the target and then settle back down to the target. Now that may not be an accurate description but that is what I hear.
My method of hammer pin manipulation doesn't have nearly the pitch movement away from the target at any point (on average). In fact, the method I use allows me to tune more directly to the pitch target utilizing the basic method that I described earlier and also which Fred has described. The control of the flexing of the pin avoids the back and forth across the pitch movement until things finally settle in. There is more guesswork in your method--how much above the pitch do I need to go so that when I apply back pressure on the pin it drops to where I want it. I don't want nearly that much pitch movement away from the target but rather can feel the amount of movement in the pin which is directly reflected in the pitch movement itself. When things are moving well on a good piano with decent rendering, I feel like I can tune directly to the pitch and stop and it stays. There is some wiggle of the pin at the end just to insure that I have not left any unreleased torque in the pin (or that I leave the slightest bit of torque where I want it--this is another separate detail for another time), but that mostly is a check.
I realize that after a pitch correction of 6-10 cents things may not be exactly where you want them for a starting point, but to that end I would say that I would prefer that you were starting from a point closer to your pitch than you are and also from a consistent starting point, either slightly above or slightly below but not a random combination of the two of varying magnitudes. That can compromise stability of the already tuned strings and unisons where there are shared lengths between notes, and make getting into any kind of working rhythm more difficult. As I've mentioned, I think this is very difficult to do accurately with an aural pitch raise, certainly for me it is.
If I can, I will post a recording of unison tuning at some point.
David Love RPT
Again, I do really appreciate posting this and I'll try and do something when I can. If done with an ETD as a demonstration tool it's easy to visualize what is happening with the pitch as well as hear it but the visual image is in many ways more telling. That presents some technical problems for me to get done.
Let me say a couple of things re stability.
Stability, or instability, comes from one of two things, or both. Either the pin itself is left in a position where it is not stable, meaning some flexing remains that will change over time, or the string segments are left unequal. It's one of those two.
With respect to the string, the more you move the string away from the target pitch, the more likely you are to leave the the segments unequal because, in fact, you are introducing a wider range of tension variability in each of those segments. If you could manipulate the pin in such a way that there was no flexing (imagine a screw stringer) then if you wanted to raise the pitch you would simply turn the screw as you played the note and incrementally raise the pitch until you hit your target. Assuming that there wasn't a serious rendering problem you might over shoot or undershoot slightly based on your aural skills or the slight delay in string rendering but you would never have to take the pitch farther away from the target than your starting point. Therefore you never introduce more deviation in the string segments from the target pitch than existed in the first place.
The question, then, is can you move the pin in such a way that it behaves like a screw stringer and tune, in essence, directly to the pitch without introducing the back and forth pitch deviation that occurs with flag-polling. And the answer is yes you can in the manner the I described and that Fred corroborated by what amounts to a counter flexing of the pin in order to remove the flagpolling effect on the pitch.
So then the other issue is whether you can do that and consistently leave the pin in a state of equilibrium because you are introducing a flexing to offset the twisting--two different stresses on the pin. But since the pin is more closely connected to you via the tuning lever, a feel for the pin being in equilibrium is much easier to develop than if the string is in equilibrium, the string being once removed, like a distant cousin, as it were.
This is what is difficult to put into a recording because the forces being introduced to achieve this are not heard. What is heard are much smaller pitch movements back and forth (if any), as I mentioned, it will sound like you are tuning directly to the pitch required. In fact, you can flex and move the pin in such a manner that when you settle the pin the pitch will actually rise to the target pitch rather than having to settle the pitch back to the target. That technique (getting to the pitch from under rather than from over) has some advantages in that the front segment will err on the side of fractionally more tension. Some arguments can be made that that has a slight advantage for stability but that's another discussion which I won't embark on here.
Forgive the typos if any, I gotta go to woik.
David Love RPT
John inspired me to go ahead and video a tuning, so I schlepped the camera into the university yesterday. I did a nice video of a practice grand tuning, but, alas, no audio due to the auxiliary mike's battery being dead (bang head against wall for stupidity). Having no other grand that needed tuning and was available, I just did the next piano on my list, a 50 year old practice Hamilton. Actually not a bad choice, as it is bottom of my barrel, but maybe middle of the road for most private clientele. This is as sloppy a tuning as I do - unless under extreme time constraints.
I did five videos: low tenor, high tenor section, low octave 6, high octave 7, and a final pass to clean unisons and listen to the whole piano. The piano was 10 - 15¢ flat, and I did my typical one pass, using offsets I entered myself (about 1/4 overshoot) rather than the pitch raise function (which usually leaves me beyond target). I used "standard fine tune" when the pitch was beyond 10¢ below pitch, switched to "concert" mode when within 10¢. Concert mode only shows 10¢ each side of the target pitch, and has a very sensitive display, so you can easily see changes of less than 0.3¢, instantly.
What you don't see is what I am feeling, which is the tuning pin moving in the block. That is an essential element, in order to know where you are. I am mostly pulling the hammer toward myself a bit while turning it (flexing the pin toward the speaking length), and also have the hammer mostly at 12 o'clock so the flagpoling is at right angles to the speaking length (essentially out of the picture, not affecting pitch). When I believe I am there, I do a very small wiggle up and down (you might not be able to see it) and want to see pitch rise and fall just above and below target the same amount. I won't hear that change, I will simply see the display begin to move slightly in each direction (the pitch change due to the flexing I am doing might be as little as 0.1¢). This is enough to ensure that things are in a stable state - together with playing the note and watching the display over some time with no hammer action.
I put the videos on my YouTube fredpianotech channel in a play list.
Thanks for doing this! Helpful to see what's going on. I didn't watch all the videos, but enough to see your method.
All I can say is that I wish I could be there and give those strings a good test blow to verify stability. That's my first pause. However, I will say I've done similar things with RCT, so I know stability is indeed possible that way. But I always do a firm test blow to confirm.
The second pause is that it's a larger pitch raise than I like to do in a single pass. For the most part, RCT does a good job of pitch corrections. But I find there are always sections that needed a slightly different overpull. YHMV (Your Humidity May Vary). ;-)
John Formsma, RPT
I kinda thought there would be doubters about the stability. I remembered to do some brutal test blows as demo when I did my original video on the grand (that turned out to be without audio), but when I did the upright, I forgot about that and just tuned as I would normally do, and only did some fairly minor forte blows. The thing that I know while I am tuning, and you don't know while watching, is what the pins felt like, as well as the checks I do as I approach target pitch, minor flexing of the pin in both directions with the hammer (jiggles) while playing the note to see just where I have got to, watching the tiniest changes of the display. Then I know how far the pin still needs to move, I feel the pin move what I think is that far, I check again with the wiggle and playing the note, watching for any pitch drift in the display. If there is any drift, I react instantly and nudge the pin a bit, etc. It is very much an interactive process, and I know from long experience that I am aware of exactly where I am at almost all times (once in a while I overshoot, my focus lapses, some pinblocks are nasty, etc. - I'm not claiming perfection).
I have done the test blow thing many, many times to check myself, and, with very rare exceptions, the pitch and the unison stays right on, not a bit of movement. But I will be sure to do that on video when I do a grand, maybe in the next few days (depending what the room access allows).
When you talk about the flexing thing and knowing how to compensate, you are describing how I tuned for years. You know how far the pin needs to move, you have a memory of how that feels, you turn the pin what you think is that much, ignoring how far the pitch changed, then you settle the pin and string back. If you guessed right, cool! If not, do it again. It is when you get into that last little nudge for really refined unisons that this becomes pretty problematic. Say twisting the pin moves pitch 10¢, but you only need to nudge pitch 0.3 - 0.5¢. How many times are you going to have to experiment before you are sure you have moved the pin that tiny amount AND the string is stable? Or do you just say, "That's as good as it can be tuned, I've spent enough time"?
Eric Schandall likes to show a technique, especially for this type of tiny pitch change, where you flex the pin in the flat direction (pitch goes a bit flat, audibly) and turn it until you feel it move the slightest amount, with no audible change in pitch, then you flex the pin to pull the string over the bearing. It is that kind of technique that led me down the path that turns out to be one David Love has also pursued.
One thing I have observed over the years, with respect to stability, is that it is most likely to be a problem when the pin just doesn't want to move that last little bit in the upward direction. It always wants to shoot past. It may move in lovely small increments right up to that last 0.3¢ and then it only wants to move a minimum of 1 - 3¢. So having shot past, you approach it from above, and it seems that you nail it (though if you are really observant, you might notice that the pin has turned farther than it really should have had to - but, hey, you got the unison beautifully clean so who's complaining?). However, the reality is that that particular string is very likely to be the one that causes embarrassment, drops 5 - 10¢ either during performance or over the first week in the home or other location, because stabilizing a string from above is an iffy proposition. If the pin doesn't want to go to that spot from below, it won't really want to from above either, so you will probably shoot past with the pin and very possibly not with the string. It will be very possible that there is enough friction that you leave an unstable situation - and a brutal test blow will very often not reveal this problem. It will only show up gradually over time, being played many times.
I have experienced this kind of thing many, many times on the same strings of the same pianos. I have analyzed up and down and around. My customers don't care that it is a problem pin/block/string, they want it in tune, no excuses, and to stay in tune. I'm supposed to be the expert. What to do? I discipline myself to approach from below always, to make that last bit of nudge with persistence and patience, to bring the string along from below as well, not allowing it to go past target. If the string was sharp, I go flat a bit (pin and string) and then pull pitch up to target, never approach the target entirely from above unless I can give a very minor flex of the pin and move the string just flat, then settle it at target. I find that if I make it an absolute rule (with the exception just given - but being very sure that this is the case) that pitch is always approached from below, I can count on stability, otherwise not. If there is minimal string bearing friction, and you can flex pitch freely in both directions without moving the pin the in block, this is far less of an issue. But most pianos have some frictional issues, and they tend not to be entirely consistent.
In any case, I certainly make no claims that my tuning method is the only best one that everyone should use. I simply put it out there, sharing where I have got to after over thirty years of experimenting with just about anything that seemed like it might work. I am happy with what I do now, as I never was until I came up with this method. So I describe it in detail in case it might help others.
What you call a pumping/ratcheting motion is the basic element of my own tuning style, has been from the beginning (I was taught to be a "jerk" tuner by the incomparable R.L. Coberly at Grayson County College - one of the best things he taught me). It allows for smaller movements of the pin, more control, and I think it helps get the strings across the bearing points better, and to break settled friction as in rusty terminations. I gauge how much force I have behind the jerk, trying to add just enough to move the pin by the amount I want it to move. Sometimes this means a lot of jerks before I get just enough to move it that little nudge that is needed. Gauging the amount of force in minute increments is where the skill lies, and when I am fatigued I don't have as much of that skill. I know some people have success with a "steady pull/push" method. I never could do that successfully with any control, though I don't quarrel with those who do.
I'm going to respond here to a later post of David Love, regarding his Harrison grand with quite a bit of bearing friction. In a situation like that, I find it is better to be pulling up on the hammer while turning it (adding flex force rather than subtracting it), trying to have it at the point where that additional flex of the pin creates enough extra pull on the string so that pitch moves with the pin. It is fine to turn the pin, and then pull the string over the bearing points, but only when friction is low enough that you can actually pull the string using flex and twist (and playing the note pretty loud and often while doing all this). When there is too much friction for that, so that you turn the pin enough to produce a 1 - 2¢ pitch change and nothing happens and flexing the pin nothing happens, it is better to add twist and flex while turning the pin in the block, as the jerking motions plus the extra twist and flex may be enough to get the string to move in sync. Otherwise, you have to turn the pin more, until you can pull to pitch, and then you have undoubtedly turned the pin beyond where it should be, so you might back the pin off in the block, estimating how much, hoping to leave it relatively stable. At least that is my approach: adapting the flex of the pin I do consciously to the hammer to the conditions at hand. It works pretty well. When frictional levels get beyond a certain point, it is simply a gambling game, and you do your best.
I decided I should try to set down a pretty detailed account of my thinking that led me to the tuning system I use, that I have been describing (similar in many ways to David Love's, but with a few differences in detail). IOW, the theory behind the practice, the thoughts and experiences that have led me to develop a particular technique and approach to tuning that is rather different from what most people do. It's a long post.
First, I don't believe there is any issue with leaving the pin itself in an unstable state. Tuning pin steel is such that as soon as you remove the twisting and flexing forces from the pin, it will return to its rest condition, essentially instantaneously. To test this notion in real life, take a piano with tight pins and VERY low string bearing friction. Just barely touch the pin, and pitch changes, that sort of piano. Flex the pin in either direction, then let go of the hammer. Pitch moves away, then returns immediately when the hammer is removed, either direction. Twist the pin (not enough to move it in the bock) in either direction, and let go. Same thing happens. Try to leave an instability in the pin: do your utmost to make it so that the string will remain temporarily sharp or flat of its stable state after you remove the hammer. Can you do it? I don't think so. If you can, I believe it is due to there being a wee bit of bearing friction.
If there is bearing friction, a little or a lot, it is quite possible to leave pitch above or below the stable point, at will. The same experiment on a piano with significant bearing friction will prove that this is so. Thus, the problem we face when trying to achieve tuning stability is centered in string friction, not in pin twist or flex.
To separate things out, look at tuning from the perspective of a screwstringer: In a screwstringer you just turn the screw, there is no flex or twist of the tuning pin involved. (BTW, Levitan's C hammer emulates this. So does a T hammer). Turn it clockwise and pitch rises, counterclockwise and pitch falls. There IS bearing friction, and the instructions inside the Mason & Hamlin tell you always to approach from below. If you overshoot and go sharp, turn it back to flat and come back up. Why? Because experience shows that coming at pitch from above will leave more unequal tension between string segments than coming from below, or at least an inequality that will more probably lead to instability, creeping over the bearing points later. If you tune one, you will notice that the pitch lags behind the screw: turn is a slight bit and nothing happens, turn a little more and pitch starts to move.
In fact, if there is a good bit of bearing friction, coming up from below straight to pitch, you might find that the piano will tend to go sharp a bit after being played a while, as the tension equalizes over the friction points. But it will be less noticeable than if you were tuning downwards in pitch, because the magnitude will be less. (A "trick" is to back off the pin just a bit after you reach pitch, no more of a turn than it took before the pitch started moving when you first started on that string - but it is guesswork). One of the problems of the screwstringer design is that you have no way to compensate for the string friction other than playing the note hard - usually good enough, but not always, and in the little experience I have tuning one, it seems impossible to get a really clean refined tuning. The steel pin in wood block design allows you to compensate for string friction by using pin flex and twist, and thereby get a more refined tuning - if you are skilled at it.
Focusing in on string bearing friction and the difference between raising pitch and lowering it: When raising pitch, you add tension to the string segment between bearing and the pin, and you can add more through the twist of the pin and by flex. The differential you can create is pretty large. Tension from the high tension segment pulls across the bearing from where the tension is lower. If you are lowering pitch, the high tension segment is the speaking length, so the speaking length is doing the pulling, and you have no way to increase its tension besides hard blows on the key. You are creating a lower tension in the bearing to pin segment, and the higher tension of the speaking length is all there is to pull the string over the bearing (unless you press on the speaking length with a dowel or something - which is a helpful thing to do in some circumstances, but not very predictable as to eventual results). To summarize, "it is easier to pull up than to push down."
You can test this on a piano with moderate to high bearing friction. "Push" the pitch flat as much as you can by pin flex and twist without moving the pin in the block. Try to get the string to go back to pitch by playing the note loudly. Then try by flexing and twisting the pin (not enough to rotate it). Now do the same on the sharp side. In my experience, I can usually pull up from flat quite a bit more easily than I can push down from sharp. Often I can't push flat from the sharp side at all, even with hard blows and pin flex and twist, but that doesn't mean the pitch won't go flat over time, back to the original stable position.
The main driving factor in pianos going out of tune due to unstable condition of the string is the blows of the hammer on the string, which momentarily raise the tension in the speaking length (when the string goes into its widest excursion) - hence that action of hammer blows will tend to pull lower tension wire from the non-speaking length, resulting in lowering of pitch. It won't "push" tension into a higher tension speaking length. It may facilitate pitch going a bit sharp (by getting the string moving) if the tension is unequal enough in that direction, but far less than it will facilitate pitch going flat when the opposite is true. And we rarely see a real problem unison due to a string going sharp - maybe a cent or two in most cases. Flat, 5-10¢ or even more can be common. That is my experience, at any rate. Bottom line: it is better to approach from below, as you have more opportunity of control, especially if there is significant bearing friction to overcome, and you will leave the string in a more stable position.
As I see it, the fundamental problem of tuning is to get the pin into the precisely correct rotational alignment, the alignment that corresponds to the string being at the correct pitch in a stable state. There is a small window of leeway if there is any string bearing friction at all, as there will be some degree of inequality of string segments that won't cross the bearing point readily, but that window is pretty small. The task is first and foremost to be able to move the pin in the block by a tiny enough amount to get it to that precise alignment, and to be able to do that with a variety of pin block situations (tightness, stickiness, sponginess, etc.). But then there is the puzzle of knowing when the pin is in the correct window of alignment: the only reference we have to go on is string pitch.
So now we come to the real heart of the issue: how to find out when the pin is in its precise rotational alignment to achieve a stable target pitch. In the normal course of intuitive tuning practice, we don't control things very much. There is twist of the pin, there is flex of the pin, there is bearing friction, and everything is somewhat chaotic in how it adds up. We may put the hammer on at whatever alignment to the pin is most comfortable to the body, resulting in a flex we don't really know about or account for. Or we put it where some authority told us to,, not really being aware of why and how that impacts the results. Pitch will usually go past target (most often multiple times in both directions), and most commonly that will mean going above target and then being "settled back." We manipulate the hammer and pin, guessing how much to pull up and push back (or vice versa), and when it seems we may probably have reached the target pretty closely, and we are tired of wrestling, we call it good enough. I am describing how I learned to tune. Eventually I began to take some aspects into account, but not in any systematic way. I more or less evolved a certain set of tricks, including the pull up/settle back "pin setting" theory. I ALWAYS went beyond pitch and settled back. And it was always guesswork whether the pin really was in the spot it should have been. And I had stability issues, not so bad, but definitely a problem when you come to the high expectations I work under most of the time.
Putting all these factors together, my solution is a simple one: to tune in such a way that the change of pitch of the string changes simultaneously with the turn of the pin in the block (as close as I can possibly accomplish that), and always to approach pitch from below. I've already described how I do that, so I won't repeat it here. The point is that I know where the target pin alignment is at all times (it's in the sharp direction unless I overshoot, in which case I go back below target), I know when I have reached it, and when I have reached it the string is also in a stable state, because I haven't created instability by my actions. When I reach target pitch, I am there. The amount of added tension in the non-speaking segment was just enough to pull the string over bearing, overcoming friction there, so when I release the hammer, the added tension will disappear, and the tension of that segment will be equal to the tension of the speaking length. Nice theory - AND it works (within the parameters of human frailty interacting with the physical world).
Re-reading this, I see it is pretty dense stuff, and rather rambling. I have been wrestling with how to describe all this for a long time, and I end up chasing my tail and becoming frustrated. I think I will call it the best I can do for now. I hope I have succeeded in explaining some aspects in a way that makes sense, and might be helpful in some way to others.
I think that's a pretty good description, Fred, and can't find much to disagree with as it reflects my own approach and for the same reasons and results (re stability). Whether you can leave some flex or twist in the pin or, perhaps, leave the pin in such a way that it is not resting solidly against the front bearing surfaces of the pinblock is a question I'm not sure about. Also, since the pin is being pulled (and twisted) by the tension from the string, does the pin react to that after you've left it? Is there some "creep" of the pin either pulling it forward (toward the string) or twisting and if so does settling the pin simply mean putting it in the position where these stresses from the string will inevitably take it? I can't answer that question but it seems that there is that possibility in which case addressing the flex and twist of the pin is a part of achieving stability.
David Love RPT
The tuning pin certainly does move after the hammer leaves it: it "untwists" and "unflexes." Whatever you were doing to it with the hammer is undone (and a large part of that is being pulled by the string, both rotationally and toward the speaking length by tension). I don't believe, though, that there is any significant "wiggle room" for the pin to be left in an unstable condition, that there is any additional creep after the initial settling. The force of the string, together with the nature of the steel pin, don't leave much room for an unstable condition - unless the torque is so low the pin doesn't hold in the wood.
That said, in my technique I will always do something of a "wiggle" "spring" motion, in both the flexing and twisting modes, but the purpose is to check to see that the string either doesn't move or preferably moves equally in both directions. It certainly doesn't seem that when I do that wiggle the pin is changing at all: I am moving it from a centered position in both directions. I could be wrong, but if so I think it is negligible enough to be ignored. I think the big issue is in the string.
It has just occurred to me that I was inaccurate in saying that Dan Levitan's C hammer, along with the T hammer, emulates the screwstringer. It does in that there is no "flexing" or "flagpoling" involved (unless you consciously introduce it), but there is definitely the factor of pin twist when using the C or T hammer (the top of the pin twisting ahead of the bottom, resulting in the string being pulled ahead of the rotation of the pin in the block.)
This is not just a minor quibble, it is an important factor to consider if using the C hammer (or a T if anyone does, and I gather there are at least a one or two out there, one writing on this list). In fact, pin twist is one of the two major factors in what I have been trying to explain (the other being string friction). So it needs to be addressed one way or another when using the C hammer.
Flagpoling is taken out of the equation by the C hammer, but when you tune with a normal hammer placed in line with the strings ("12 o'clock" or as close as you can get) you have taken flagpoling out of the equation as well (the flagpoling that you can't control is happening at right angles to the hammer, hence at right angles to the tuning pin, hence not a factor in changing the pitch of the string). For purposes of what I have been describing, the techniques would apply just the same to a C hammer as to a standard hammer.
I have found I can use a 12 o'clock position comfortably, though it took me a while to figure out how to adapt. I sit with my body nearly at right angle to the piano, facing the bass. I turn the bench so that it mimics my seating stance (this makes a big difference). And then I simply reach over and hold the end (round knob) of the hammer, and try to use my body weight as much as I can, leaning slightly one direction or the other as needed. Sometimes I stand up for a while. I do get as far as 2 o'clock sometimes, but often it is problematic so I revert to 12. But depending on exactly what the relationship is between pin torque and string friction, other alignments can work, at least for certain sections. I might only shift to 12 o'clock for the final steps, if that seems to be needed.
I might add that the extra hammer length (13" as opposed to 11"), while it means that the arm is extended farther, actually makes it easier because of leverage, compensating for the less direct arm angle. If the pins are VERY tight, I stand mostly, and lengthen the hammer.
I have now done a grand video (actually a series of four), and have uploaded to YouTube here. In this case the piano is a Steinway B, 50 years old with its original strings, so it is a bit of a challenge in terms of stability and fine tuning, an above moderate degree of string friction. In the first two clips, low tenor and over the treble break, I did some hard test blows on a few notes to show that they are, indeed, quite stable when I am done. You can see my arm and the hammer, and the angle is better (than with the upright) for seeing what I am doing in terms of up/down and the muscular movements of my arm (which are transferred to the hammer, but you may not see the hammer move).
I chose to show tuning over the break because it is quite a hard area to tune, particularly on this piano. I thought I'd show my own approach, which is somewhat slow and patient, rather finicky, insisting on approaching pitch from below. This is not a 45 minute piano, though I can usually do it in 1:15 if the pitch change is relatively small, as this one was (all within 10¢).
The RCT is set to Concert mode, so the whole display shows from 10¢ flat to 10¢ sharp of the target pitch - if you are outside that range, you can't see the rotating disc. The resolution is quite sensitive, so there is obvious change in rotation/blush in the range of 0.3¢, and it is still apparent in even closer parameters.
The final video is cleaning up unisons, then listening to the piano. The whole process was simply a normal tuning, with the exception of throwing in the hard blows as a demo.
Glad the technique seems promising to you. A couple comments: It is important to pay close attention to the sync between feeling the pin move in the block and the amount of pitch change there is. If you feel the pin move a couple tics, enough in your experience to change pitch 1¢, say, and pitch hasn't changed at all, you need to change what you are doing.
My approach is very fluid, The norm is to flex the pin "down" (in the direction that will make pitch go flat) while pulling up (turning the pin in the sharp direction), but that is negotiable and variable. First there is "how much down" as a starting point. If I notice that pitch is not following the turn of the pin closely at first, my first response is to spring the pin a bit, flexing and twisting (but not turning) to see if the pitch can be coaxed up and how easily. If I can manage to get pitch to where I think it should have been by this means, I will continue but with less down flex.
If the springing doesn't move pitch readily, I will change tack and try turning the pin first with no down flex (neutral), then, if necessary with up flex. I want pitch to follow the movement of the pin almost at all times, slightly but not significantly behind. I especially don't want to get far behind when there is a lot of friction in the string, because it will be difficult to tell when I have reached a stable point, and it will be more difficult to "spring" the string to precisely the target without overshooting. When I am just barely below target pitch, I generally try to nudge the pin without changing pitch, then spring to pin in a controlled way to move the string that last bit - often several tries to get it to happen.
There is a continuum of string friction versus pin twist. When string friction is low and pin torque (hence pin twist) is high, you would want to flex down the maximum, so flex will counteract twist on a one to one basis (friction not entering in, or very little). When string friction is high and pin torque is low, you need to flex up the maximum: in this case there is minimal pin twist to help pull the string over bearing poins, and maximum drag on the string, so you are needing to overcome those two factors. And then there is everything in between. It's a matter of experimenting with each piano and each string and pin to come up with the right approach - sounds more complicated than it is.
I have emphasized a preference for any instability I leave in the system tending in the up direction, but that is somewhat more conceptual than practical: if true, it should be very small. I emphasize that concept because I have found through my own bitter experience that it is very easy to do what seems like very precise, refined tuning in the downward direction, when, in fact, the precise result you achieved is very unstable. As I have analyzed various problem notes and experiences where strings have shot 10¢ or more south (when I thought I had nailed that tuning), I have come to the conclusion that it happened most often when I had shot slightly past in the sharp direction, then settled back gradually, but wasn't paying enough attention to what I was feeling in the pin. The pin would move as much as 10¢ worth before the string would start to ease slightly and gradually down to target. I'd get to a refined target, I could pound and nothing would move, but next day that string would be 10¢ or more flat. Other times it happens when pitch was significantly sharp, and the strings seemed to be rending well, so I was lazy and didn't make certain to go below pitch, for sure below pitch, and pull back up. It can happen when string friction isn't all that bad, on a five-year-old grand, for instance.
So I am paranoid (with good reason), and ALWAYS tune in the up direction, and ALWAYS err on the side of the string wanting to go sharp - but as little as possible. It's a discipline that has served me well over the past few years. It took self-discipline to learn the techniques - it is not immediately intuitive, but it does become habitual with time.