On Aug 24, 2009, at 10:29 AM, Mark Cramer wrote: > IME, once escapement is synchronized via the jack, if the jack is > out of > line, it indicates an error with one of my other a/t adjustments... > i.e. > drop a bit wide, lever a bit low, etc. and I will need to go back > and find > it. So, jack position can be a very precise after-touch diagnostic > as well.. > that is if we don't fudge it by merely lining it up to the core. ;>) With respect to Eric S's "final adjustment," I think he is on the right track in the sense of looking for a very fine and crisp feel of the jack and drop being simultaneous. But I don't think that adjusting the jack position (relative to the knuckle) is the right way to get there. I prefer to diagnose and decide what is wrong. Could be only one of three things: letoff, drop, or jack position. So figure out which one, and correct that. And I have a somewhat different method of checking. Eric does it by pressing the key down. I prefer to take the key out of the picture. I get a more sensitive feel by simply using a finger to lift the wippen, positioned under the lever a little forward of the jack. Raise until you hit the resistance of the rep spring. Ideally, when you push through against that resistance, the jack just immediately begins to move. If it is wrong, the jack movement will either be delayed a bit, in which case the jack will have risen above the level of the of the rep lever before moving; or the jack will move first, in which case you will have felt a little bump before the big bump (jack tender contacting the button before the rep hits the drop screw). It kind of goes along with lightly tripping each jack to check for alignment of the rep top with the top of the jack. A similarly very sensitive touch is needed, and it can go pretty fast if you have done good work. If not, it will tell you real fast that you haven't, and maybe you'll decide to go through and advance or retard all the drop adjustments a tad, as an example, then re-check. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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