On Aug 24, 2009, at 7:05 PM, Mark Cramer wrote: > On a sample note; if these *four* adjustments (presuming you meant to > include rep. lever height) do NOT result in synchronization, AND > correct > jack alignment to the knuckle... yes, we would diagnose the other > three > tolerances and make a global correction before continuing with jack > position. Hi Mark, I think that in general we are in agreement on this. My intent was simply to add some additional details and wrinkles to the conversation. I guess I would have to agree that the rep lever height needs to be taken into consideration if trying out the action with the hammers up out of the way. If the rep lever top is much above the jack top (due to relatively weak springs or poor regulation), it will mean the lever will hit the drop screw earlier than it would in real playing conditions, where the jack top and the rep top will both contact the knuckle and the gap will disappear. So this makes the method of checking with hammers raised less precise than one might expect. A couple other thoughts about the ways in which these factors interact with one another, and affect the regulation: If the jack is set farther under the knuckle, the tender will hit the letoff button earlier. Hence, to make the drop simultaneous, the screw will need to be lower, so drop is also contacted earlier. Hence, jacks farther under knuckles means greater drop distance. And, of course, vice versa: set the jacks "less under" (I can't think of a good way to put that) and simultaneous drop will be higher. The former means you could have a little more aftertouch and not worry about string contact, The latter means you need to reduce aftertouch. All very subtle, but significant to how the action feels and responds. Along with how much the jack scrapes along the surface of the knuckle. Add all the factors, and you definitely feel the difference. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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