Jacob Doll action brackets

[Keith Roberts]

Like I was saying, why make a set when all you have to do is cut and shim
the old brackets. They expanded an 1/8" in 110 years. That still doesn't
tell me the size of the original bracket so the placement of the whippen
rail has to be adjustable. Loo k on page 124 in the Shaff catalog and you'll
see the bracket..
Keith R
----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Friday, January 24, 2003 3:41 AM
Subject: Re: Jacob Doll action brackets


> Gordon might have the right idea, but you might get a stronger unit if you
epoxy-laminate some hard maple together and cut them out of that on a band
saw. I guess you could also take a hunk of Delignite pinblock material and
cut them out of that. I shouldn't think if too difficult to do.
>
> Terry Farrell
>
> ----- Original Message -----
> From: "Keith Roberts" <kpiano@goldrush.com>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: Friday, January 24, 2003 2:19 AM
> Subject: Re: Jacob Doll action brackets
>
>
> > I was thinking if I had the original specs or drawings it would help.
Maybe
> > Shaff can find them for me.
> > >From my measurements, the hammer flange center pin is about an 1/8" to
3/16"
> > high for a bore distance of     2 1/16" in the tenor and treble
sections.
> > That's kind of a short bore distance as you're almost drilling through
the
> > felt on the bigger tenor hammers. So I could cut about 3/16" off the
front
> > foot of the action bracket to bring the hammer rail down to same height
at
> > each bracket. The capstans have plenty of room to move down. I guess the
> > whippen rail has risen about 1/3 as much as the hammer rail. So my
second
> > guess would be to cut about an 1/8" off the rear foot so as not to
rotate
> > the bracket and shim the wippen rail up and to the front until I have an
> > action spread in the 113 mm range and the Magic Lines or lines of
> > convergence are as close to the optimum as can be. The action spread now
is
> > 116.7mm in the treble and 116 in the bass. It doesn't look like these
> > brackets are expanding at the same rate. Just the one treble bracket is
> > showing a crack along the base.
> > So now that I've moved the whippen rail to the front
> > 2 to 3mm, I have to cut the back off the bracket or notch the keyframe
and
> > move the stack back in order to center the wippens over the capstans.
The
> > key ratio is 2.08 so the capstans are in the right place, I think. Then
I
> > hope and pray the strike line is back to where it should be and the
brackets
> > aren't jammed into the damper trap work.
> > The hammers are hung at 5 3/16" or 132mm, center line to center pin.
> > Renner has exact replacement whippens and shanks.
> > The wippen number is 913 051. The shank/flange
> > # 913 007. I hope someone is following this. If you know this action
> > geometry,  is my scenario correct? The action seemed to have a spongy
feel
> > after I moved the whippen rail to the front. Is this because I
compromised
> > the wippen lever ratio by not moving the stack?
> >
> > Really I'm hoping some one will have some in a drawer in their shop.
Please.
> > Keith Roberts
> > kpiano@goldrush.com
> > Associate PTG
> >
> >
> >
> > > Make pattern, cast out of epoxy/epoxy composite?
> > > ("Liquid Steel")?
> > >      Thump
> > >
> >
> >
> >
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