[CAUT] CAF

[Fred Sturm]

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