Hi Joe"
If your dip is, by intent, even throughout to careful measure, you have chosen what is called dip priority, where the aftertouch is not a controlled variable and can differ. If you are doing aftertouch priority, that is your controlled variable, and dip will vary. I am an aftertouch priority guy, so in an action rebuild I set a quick and dirty dip that is sufficient to make the regulation functional so as do the let off, blow distance, checking height, and so on. I will revisit the regulation several times before the piano goes out the door, and I want my regulation pretty stable and accurate before I finally set the aftertouch. In a perfect world, my regulation would be so good that aftertouch and dip would be the same throughout. But even new parts are variable, small errors in our regulation creep in, and so on.
What is interesting is that dip is dip. If we set the dip to .390" then, even as the other measure can vary, that setting does not change. But aftertouch sure can. When you set the regulation to what you is refined and, say the dip feels too shallow. You check your measure and its still .390. But you have little or no aftertouch. I am just thinking that aftertouch can be a bit of a canary in the coal mine for existing action problems that you have not noted and addressed. We can quantify our measure for aftertouch, but we often feel the anomoly first.
I think you are overthinking it a bit. Set the letoff as desired and varied through the scale as you prefer, more in the bass, less in the treble. Set the blow distance to the desired measure. Make the dip deep enough that you will not have to remove punchings to achieve your 1.25 mm aftertouch. Whether by a weight or by finger, add or subtract punchings until you just go through letoff and no more.
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William Truitt RPT
Bridgewater NH
(603) 744-2277
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Original Message:
Sent: 01-19-2026 19:09
From: Joseph Burros
Subject: Refining Key Dip for accurate Aftertouch when Letoff differs in the Bass, Tenor, and Treble sections
I'd like to get some feedback about my approach to attaining even Aftertouch across all keys, even when the amount of Letoff differs between the bass and treble strings. I am setting the Letoff as close as reasonably possible on all keys, so that means that the Letoff will be further from the keys in the low bass, because of more movement in vibrating bass strings, and much closer in the high treble, because string vibration movement is less as you go up the keyboard.
Now, let's say that Letoff in the bass section is 1/32" or 0.79mm further from the string than the treble section. I am wanting an Aftertouch of 1.25mm on all keys. Obviously if my Key Dip remains the same across all keys and my hammer blow distance is the same across all keys, my Aftertouch will be less in the bass and more in the treble section because of the differences in Letoff.
My solution, after consulting with more experienced technicians and reading Journal articles is to vary the key dip across the entire keyboard, so that I can achieve the same Aftertouch on all keys. My understanding right now is that experienced players will not notice small differences in Key Dip but will definitely notice differences in Aftertouch.
I will first start in the middle of the keyboard setting my preferred Key Dip and Aftertouch. As I work my way down toward the bass section my Key Dip will become greater in order to compensate for the increased Letoff distance. My Aftertouch will remain a constant 1.25mm.
As I work my way up toward the high treble section my Key Dip will lessen in order to compensate for the decreased Letoff distance. My Aftertouch will remain a constant 1.25mm.
I welcome any feedback on this approach and any suggestions on how to approach this differently.
Thank you!
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Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
https://fminewengland.wixsite.com/fmi-new-england
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