aftertouch vs jack escapement

[John M. Formsma]

I assume you're shining a light in there to see how much clearance there 
really is. Low light can play tricks on our eyes. And you are trying it 
on more than just one sample key?

Are the action parts new or old? That would make a difference. If old 
and worn, you can't get it exactly to "spec." You must work with what 
works best overall, all things considered. I don't think you would have 
to go with the blow distance at 1.5" but it's been a while since I 
regulated an upright with worn parts.

Why not increase the dip to 10 mm? That would give you a bit more 
clearance from the butt and keep your aftertouch within .050"...right? 
Some say aftertouch should be .050 anyways.

A greater blow distance requires a greater dip, and the inverse is true. 
So you play around with decreasing the blow or increasing the dip to 
find what makes it work best. I'd try the dip at 10 mm first, then 
slightly decrease the blow distance if that didn't work.

Thankfully, there are not an infinite number of solutions to the 
regulation problem, though it sure seemed that way at first. Once I 
figured that out, things became more solvable (at least to me). <g>

JF



ed miller wrote:
> I'm regulating a Knabe upright. I’m having a problem juggling 
> acceptable aftertouch vs. an acceptable amount of jack escapement out 
> from under the hammer butt.
>
> With blow distance set at 1.75", let-off at 1/8", key dip at 3/8" and 
> checking at 5/8".... aftertouch is about .040". With the dimensions as 
> such the key feels like it plays well. In previous regulations I would 
> have been very happy with this.
>
> However, this time I'm regulating according to Bill Spurlock's 
> Vertical regulation pamphlet. In it he talks about aiming to have jack 
> escapement be 1/16-1/8" out from under the hammer butt when the key is 
> fully depressed. With all of the above dimensions in this Knabe 
> upright the jack doesn't rotate completely out from under the hammer 
> butt.
>
> Spurlock suggests decreasing the hammer blow distance to allow the 
> jack to escape further. When I do this my aftertouch becomes too 
> great. If rather, I increase the key dip to allow for more jack 
> escapement aftertouch becomes too great again.
>
> In order to have the jack escape properly I would have to decrease the 
> hammer blow distance to under 1.5” (I know because I tried it). As I 
> suspected my aftertouch shot up, it was then .100”. If I then decrease 
> key dip, the jack doesn’t rotate far enough.
>
> Then I tried to make my checking earlier. Even at less then .5” 
> checking the jack doesn’t completely get out of the hammer butts way 
> before it is caught.
>
> What do I do????
>
> Thanks, Ed
>
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