[CAUT] Upright geometry problem (Nordiska)

[Fred Sturm]

You might look carefully at the action brackets and how they are  
aligned and attached top and bottom. Sometimes the angle at which the  
whole action assembly is held relative to keys and strings is the key  
to this sort of problem. For instance, sometimes the butt leather and  
its curve are leaning back too much and ought to be more upright. The  
angle of that curve of leather has a lot to do with whether the jack  
can clear it. In which case Wim's suggestion to shim back the wipp  
rail is a good quick fix. Often you can move the whole assembly a  
good bit without getting the capstan to wipp cushion (or is it  
sticker cushion in this case?) too far out of whack. Maybe whatever  
is holding the bottom was placed wrong or shifted or bent during  
shipment. Or the brackets could have cracked due to a drop.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu



On Oct 11, 2007, at 1:20 PM, Jim Busby wrote:

> List,
>
>
>
> I’ve never had to do a major geometry tweaking of an upright, but  
> this new Nordiska needs help and maybe you have some ideas;
>
>
>
> Problem: Bobbling hammers due to not enough aftertouch (Hammers are  
> bouncing off jack. No space between jack and buckskin on any blow)
>
>
>
> As it stands here are the vital specs;
>
>
>
> Blow 42mm (Too short)
>
> Dip .450 (Way too deep)
>
> Letoff 1/8”
>
> Checking 5/8”
>
> (Lost motion has been regulated)
>
>
>
> If I make the let off 3/8” to 1/2 “ it begins to work but this is  
> obviously bad.
>
> More dip would make it work… (Anyone have a 12.5 mm dip block??)
>
> Less blow would also be ridiculous…
>
>
>
> Seems like I need to move capstans back. No?
>
>
>
> Any other wisdom out there?
>
>
>
> Thanks,
>
> Jim Busby BYU
>
>

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