Knabe Bridge Repair

[Farrell]

I think what he is talking about here Richard is not the strings themselves, but the bridge-top-to-string termination point. If the bridge cut for the forward termination is on an angle, as the string works its way into the bridge cap over the years (or if you plane the bridge cap down a bit for refurbishing), the forward termination point between the bridge top and the string moves forward - but of course, the termination point between the bridge pin and string will stay the same (assuming the angle of the pin is in a plane perpendicular to the string line).

If the forward edge of the bridge cut is vertical (in a plane perpendicular to the string line), as the string migrates downward over time (or if you plane the bridge cap down a bit for refurbishing), the forward termination point between the bridge top and the string will remain stationary, and at the same point along the string line as the pin (assuming it was there originally).

I can only assume this setup tends to run into problems on occasion with pins working loose because of the reduced bridge wood supporting the pin.

Terry Farrell
  
----- Original Message ----- 
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: <pianotech@ptg.org>
Sent: Sunday, April 07, 2002 6:06 AM
Subject: Re: Knabe Bridge Repair


> Erwinspiano@AOL.COM wrote:
> 
> Dale could you expound a bit more on this ? I'm not quite sure I follow
> what you mean by strings creeping forward. And I would like to hear more
> on this vertical cut. I havent seen a Knabe since...well way before I
> moved over here anyways.
> 
> Thanks
> 
> 
> > I've seen many of these types of configurations and they seem to work.
> > I've also seen a vertical cut straight down about 2mm thru the center
> > line of the bridge pin holes .The idea being that as the string sinks
> > lower into the top over time that the stings won't also creep forward
> > which they will over time and tooo much string seating. Because of the
> > vertical cut they simply sink lower against the pin but maintain
> > termination. On bridges that the notches were cut too shallow on the
> > string can actually be damped by ttouching the wood in the notch as it
> > creeps forward. Hey time marches on.
> >         Also as you sand down the bridge top just remember that the
> > farther down you go the less and less your bridge pin side bearing
> > will be and  many Knabes didn't have that much to start with.
> >
> > ........Dale Erwin
> 
> --
> Richard Brekne
> RPT, N.P.T.F.
> Bergen, Norway
> mailto:rbrekne@broadpark.no
> http://home.broadpark.no/~rbrekne/ricmain.html
> 
>