[CAUT] wacky backchecks and Knabe blow distance

[Keith Roberts]

Like Jon said move the capstans back. You will have to cut the heel off and
shorten it and put some more wood on the key so the capstan isn't sitting so
high out of the key. Isn't there enough of a heel on there to come up to the
magic line if you remove most of it?

You don't need much movement on the wippen effort arm to raise the action
ratio quickly. The fact that the key ratio is also going up when you move
the capstan back makes this a really good move. Did you change the original
knuckle position?

You should feel lucky. I get all the weird ones in Dales shop. I am doing  a
Conover and the leads in the back action were about to split the arms and
the replacement parts didn't fit quite right  but I opened my big mouth and
said, "we can move the original rail forward and up and the new ones will
fit as long as we take some off the lift rail." Now I'm modifying an old
back action to fit new parts. It looks like the center pin will move towards
the tray lift pivot point as to eliminate scrubbing. The sos rod will move
away from the back checks. I get to put capstans under each lever. What a
pain but so nice to regulate. I'm sure there is going to be something else
though. I'm to finish it up tomorrow.
Good luck,
Keith






On 10/15/07, Barbara Richmond <piano57 at insightbb.com> wrote:
>
>  Thanks, Keith.
>
> This is the first time I've worked on a grand that seemed to call for 1
> 5/8."  It just seemed weird.  I've talked with a couple friends and they
> assured me that I've lived a very protected life.  :-)
>
> Barbara Richmond
>
> ----- Original Message -----
> *From:* Keith Roberts <keithspiano at gmail.com>
> *To:* College and University Technicians <caut at ptg.org>
> *Sent:* Monday, October 15, 2007 2:50 PM
> *Subject:* Re: [CAUT] wacky backchecks and Knabe blow distance
>
>
> Are you talking blow distance as a function of dip/action ratio or
> clearance above the hammer rest rail? Bore distance will solve the latter.
>
> Keith Roberts
>
>
> On 10/15/07, Barbara Richmond <piano57 at insightbb.com> wrote:
> >
> >  Sorry Jon Page, I'm going to post to both lists.
> >
> > Speaking of wacky backchecks--no I didn't do this--but have put the new
> > action in and am roughing things in (pay no attention to that hammer line, I
> > decided the sharp key height had to come up a bit.  I have some sample notes
> > set and really need to fix these backchecks before continuing--but first...
> >
> > Has anyone worked on a 5'8" or so Knabe grand (late 1920s) where it was
> > difficult to get 1 3/4" blow distance?  Is it <normal> (for this age, model,
> > whatever), more or less, to have to go a bit narrower, like 1 5/8"?
> >
> > This is the first time I've worked on a piano that was this screwed up.
> > I've learned a lot.  :-)
> >
> > Barbara Richmond, RPT
> > near Peoria, Illinois
> >
> >
> >
> >
>
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