Jacob Doll action brackets

[Keith Roberts]

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
>