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Is it measured at the front of the key?
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I measure it at the jack. For grands, the jack needs to be halfway between the knuckle and the rep. lever felt at key bottom. For the upright, there should be about 1/32" clearance between the hammer butt and the jack top at key bottom.
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Let-off, drop, aftertouch. By pushing the key slowly without the hammer catching, the hammer not touching the strings.
If the let-off is at 1 mm from the string, the drop should be at 2mm, and the aftertouch will rise by 1 mm. It's like 1 2 3. Break 1mm, drop by a mm, and then back up 1 mm. The numbers vary enormously, I used these numbers to illustrate how I measure aftertouch.
So, aftertouch should be set by varying dip and blow distance in order for it to reach the same level as the let-off.
An upright action is altogether different.
All the best
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Thanks but I still need some more elaboration.
When they say that aftertouch is set at, say, 0.045", (1 mm) where is this measured? Is this the space between the front of the jack and the rep lever felt at key bottom? Or is this measured at the key itself?
Pardon my ignorance. I cannot find this in the books.
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the hammer from the string.
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Is it measured at the front of the key? The method that I use: 1. Place a .045" (or whatever the desired AT is) paper/cardboard front rail punching on top of the felt front rail punching. 2. Using a 300g weight, slowly depress the key and adjust until the action goes through escapement by gently tapping the key bed. Generally, I adjust the hammer blow to achieve this, but you could also adjust dip. For more in depth discussion, refer to "Piano Shop Trade Secrets: Measuring After Touch" in the October 2002 issue of the PTG Journal, by John Hartman.
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Is this the space between the front of the jack and the rep lever felt at key bottom? Or is this measured at the key itself? Just to be clear from my post immediately above this one, .045" would be measured at the front of the key. This is the most accurate way of setting after touch, IMO.
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Let-off, drop, aftertouch. By pushing the key slowly without the hammer catching, the hammer not touching the strings.
If the let-off is at 1 mm from the string, the drop should be at 2mm, and the aftertouch will rise by 1 mm. It's like 1 2 3. Break 1mm, drop by a mm, and then back up 1 mm. The numbers vary enormously, I used these numbers to illustrate how I measure aftertouch.
So, aftertouch should be set by varying dip and blow distance in order for it to reach the same level as the let-off.
I understood this just now. I can see how the hammer lets off at 1 mm then drops by 1 mm, then rises 1 mm to where the let off occured. Is that correct? Thanks.
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Let-off, drop, aftertouch. By pushing the key slowly without the hammer catching, the hammer not touching the strings.
If the let-off is at 1 mm from the string, the drop should be at 2mm, and the aftertouch will rise by 1 mm. It's like 1 2 3. Break 1mm, drop by a mm, and then back up 1 mm. The numbers vary enormously, I used these numbers to illustrate how I measure aftertouch.
So, aftertouch should be set by varying dip and blow distance in order for it to reach the same level as the let-off.
I understood this just now. I can see how the hammer lets off at 1 mm then drops by 1 mm, then rises 1 mm to where the let off occured. Is that correct? Thanks. Yes. Though, do note that he says "the numbers vary enormously". 1mm is probably too close for let-off in most applications; 1.5mm for treble/ 3mm in bass is a good general spec for let-off. The hammer should drop about 1mm from let-off, and then raise some when going through after-touch.
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Thanks again, beethoven!
I guess measuring at the key front will be more reproducible for me.
Last edited by electone2007; 12/02/12 11:09 PM.
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Actually, if you put the 0.045" punching on the key pin, that is where you are measuring the aftertouch, not the front of the key. If you decide on a tolerance, that should be the point where it lets off, and if you add a punching the thickness of your tolerance, it should not let off. A 0.010" punching for the tolerance is close enough. You can hardly expect felt to be uniform enough to be any more accurate than that.
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Thanks again, beethoven!
I guess measuring at the key front will be more reproducible for me. Sorry if I confused you, but the measurement is not literally at the key front; it is at the key pin. I meant "front of the key" as a general term, as opposed to "the front of the jack and the rep lever felt at key bottom". It should also be noted that the mass of the weight will change your results. A 300g weight will produce different results than a 400g weight with the same .045".
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Thanks, BDB and beethoven! That's what I thought!
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Actually, if you put the 0.045" punching on the key pin, that is where you are measuring the aftertouch, not the front of the key. If you decide on a tolerance, that should be the point where it lets off, and if you add a punching the thickness of your tolerance, it should not let off. A 0.010" punching for the tolerance is close enough. You can hardly expect felt to be uniform enough to be any more accurate than that. Greetings, In a performance setting, .010" is a huge tolerance for aftertouch. In a church choir room, not so much. I set dip by setting the aftertouch, which is where most pianists gauge evenness of action. I consider aftertouch as that key travel which occurs after the jack is no longer supporting the weight of the hammer, and before the key's motion is stopped by the front punching. After the blow and let-off are done, I set aftertouch by altering a previously set static dip, usually .390" on an older Steinway. If I have to deviate from that depth, in order to get an even aftertouch, .007" is as far as I allow the dip to vary before I start moving the hammer height. To determine the bottom limit of the key travel, I use my sense of touch to depress the key on the selected thickness of punching, ( I usually favor .035" with moderately firm pressure). Using a thicker punching to measure with firmer pressure will give a more consistent result that a thinner punching with light pressure. Whatever combo works for a given tech's sense of touch is the best way to do this. The object is consistency first and foremost. If I am using the Crescendo punchings, I will often be using the .002" to achieve discernable differences in aftertouch. I can't tell a .002" difference in key dip, but in a regulating zone, that difference can be felt in aftertouch. And if I, as a tech can feel it, I assume my customers can, also. Regards,
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we measure a bit more than 10 mm with the keyblock because it is easier to feel it when it is a hair lower from the neighboring key
Accesoirly, that way we have more the supposed 10 mm key dip 5 mm from the edge of the key.
Then one state of 1mm aftertouch as a good moderate value, and then use a .75 carboard to verify it.
All those are not so precise values. On some actions, when you have .75 aftertouch, the feel is in fact of a large 2 mm one...
As many keys are not level when they are at full dip, I cross check left and right side (but in fact I make samples on D's and A's then I even the level of the other keys at full dip, by feel. and in the end what counts is the even aftertouch sensation; If you cannot ascertain it you cannot regulate the sharps well, so the cleaner method is to use a 0.75 shim and regulate the hammer travel so it just barely begin to drop, jack is still touching the knuckle probably.
Then once you know the white keys have an even aftertouch, use that aftertouch sensation and reproduce it on the sharps, that time with paper front punchings (assuming the sharps are leveled so they dont go too low at full dip, so if you dont know the original sharp's height samples are necessary)
Last edited by Kamin; 12/03/12 08:50 AM.
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... I even the level of the other keys at full dip, by feel ... Kamin To clarify, the resulting key dip is exactly the same for all naturals and for all sharps?
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 140cm
Ibach, 1905 F-IV, 235cm
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No, the aftertouch sensation may be the same, for the sharps I don't measure the dip, even if I can check at large by pushing on 3 or 6 black keys together, then you feel/see if their dip is even. Checking the level of sharp at full dip vs the white keys provide also some informations)
Sharps have generally a different leverage than white keys (hopefully not too different , but there are extremes)
Theoretically what matters is that the hammer motion is the same for sharps and white keys, I have even no idea of how much is the sharps dip.
I also sometime find easier to feel letoff and aftertouch with more than one key at once, 3 white keys together for instance, but the usual and best tip is to use the 3d fingers of each hand together on one key, for after touch you feel is then twice , way more precise.
try to have the 3 fingers in a row to push on 3 white keys together (idem for sharps) I like that to check the eveness of letoff/drop, but it is regulated individually, and what is difficult there is to manage the key so you stop it before aftertouch, just wen drop begins. Standing on the back of the action allows to have the fore arm quietly installed on the hammer rail, then maximum tactile feedback from the key, but comparison with neighboring key is not good.
Working on new actions or new parts is necessary to get the feel for that, with parts that are not uneven.
The more you use your sensations for regulations the nearer you are of the pianist
Last edited by Kamin; 12/03/12 08:44 AM.
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No, the aftertouch sensation may be the same, for the sharps I don't measure the dip, even if I can check at large by pushing on 3 or 6 black keys together, then you feel/see if their dip is even. Checking the level of sharp at full dip vs the white keys provide also some informations)
Sharps have generally a different leverage than white keys (hopefully not too different , but there are extremes)
Theoretically what matters is that the hammer motion is the same for sharps and white keys, I have even no idea of how much is the sharps dip.
I also sometime find easier to feel letoff and aftertouch with more than one key at once, 3 white keys together for instance, but the usual and best tip is to use the 3d fingers of each hand together on one key, for after touch you feel is then twice , way more precise.
try to have the 3 fingers in a row to push on 3 white keys together (idem for sharps) I like that to check the eveness of letoff/drop, but it is regulated individually, and what is difficult there is to manage the key so you stop it before aftertouch, just wen drop begins. Standing on the back of the action allows to have the fore arm quietly installed on the hammer rail, then maximum tactile feedback from the key, but comparison with neighboring key is not good.
Working on new actions or new parts is necessary to get the feel for that, with parts that are not uneven.
The more you use your sensations for regulations the nearer you are of the pianist I completely agree - I never measure sharp key dip. I set it so that the aftertouch coincides with that of the naturals. (This means it happens late in the game during a full regulation.) To me it doesn't make any sense to even try to set sharp keydip with a tool.
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