Bedding Blues

[David ilvedson]

Hey I had a 50/50 chance.  I should have just kept my mouth 
shut for a little longer...

David I.

Date sent:      	Wed, 09 Feb 2000 20:05:57 -0500
To:             	pianotech@ptg.org
From:           	Jon Page <jonpage@mediaone.net>
Subject:        	Re: Bedding Blues
Send reply to:  	pianotech@ptg.org

> David,
> You had it right the first time. A wedge driven into a kerf on one side of
> a board will bow in that direction. So if the center is high, a shim placed
> on the bottom will flatten it out. Actually a long tapered wedge can be
> driven in the appropriate distance. A cut is made about a fourth to one
> third the thickness into the rail. I have used a router with a straight bit
> and
> set the guides to make the taper. A long spline cut to the same taper can
> be driven in to straighten it out. A few may be needed.
> 
> I think it was Yamaha which did this on grand keyframes years ago.
> 
> Kerf's up,
> 
> Jon Page
> 
> At 04:08 PM 02/09/2000 -0800, you wrote:
> >Yeah, If you wedge from the bottom it forces it up...oops....
> >
> >David I.
> >
> >From:                  "Paul" <tunenbww@clear.lakes.com>
> >To:                    <pianotech@ptg.org>
> >Subject:               Re: Bedding Blues
> >Date sent:             Wed, 9 Feb 2000 13:34:56 -0600
> >Send reply to:         pianotech@ptg.org
> >
> >> David
> >> I used this wedging technique on a warped Kawai key frame. The cut(s) was
> >> made in the top of the key frame and veneer was epoxied in the kerf.
> >> Keyframe bedded perfectly and to date there has been no problems with it.
> >> 
> >> Paul Chick
> >> Plainview MN
> >> ----- Original Message -----
> >> From: David ilvedson <ilvey@jps.net>
> >> To: <pianotech@ptg.org>
> >> Sent: Wednesday, February 09, 2000 12:15 PM
> >> Subject: Re: Bedding Blues
> >> 
> >> 
> >> > Consider making a cut on the bottom rail and putting in wedge
> >> > which will bow it down?
> >> >
> >> > David I.
> >> >
> >> > Date sent:      Wed, 09 Feb 2000 18:22:45 +0100
> >> > From:           Richard Brekne <richardb@c2i.net>
> >> > To:             "pianotech@ptg.org" <pianotech@ptg.org>
> >> > Subject:        Bedding Blues
> >> > Send reply to:  pianotech@ptg.org
> >> >
> >> > > Hi list
> >> > >
> >> > > Ok.. I got this Schimmel long 6 footer, and it simply wont bed right..
> >> > > lots and lots of spring in the middle tenor (# 25 - 40) which causes
> >> > > this unbelievable bounce in the hammers at rest while playing hard, and
> >> > > causes lots of lost power.. After doing everything possible to correct
> >> > > the bedding and getting nowhere I discovered that the balance rail is
> >> > > way off from flush with the framwork on the keyframe.
> >> > >
> >> > > This particular configuration is such that the balance rail is cut out
> >> > > too accommidate the cross boards of the keyframe, and they should
> >> > > present a flat surface where they are joined. But at key 35 or so on
> the
> >> > > treble side of the crossboard the balance rail is about 0,70 mm off
> >> > > (away from the keybed).
> >> > >
> >> > > All keyframe screws are tightened down as much as I can get them. For
> >> > > the moment I simply added a 1mm front paper bushing to the area (the
> >> > > balance rail is also warped upwards in the tenor section, and bends
> >> > > upwards and away from the bed again from about key 50 onwards, tho
> >> > > bedding screws take care of that problem)
> >> > >
> >> > > I am wondering what is best to do here... I could install a "sleeper"
> >> > > bedding screw right in the middle of this section, or I could perhaps
> >> > > plane the whole underside flat again,  or perhaps build up the
> offending
> >> > > part with some laminate..
> >> > >
> >> > > Advice boys and girls ???
> >> > >
> >> > > Richard Brekne
> >> > > Associate PTG, N.P.T.F.
> >> > > Bergen, Norway
> >> > >
> >> >
> >> >
> >> > David Ilvedson, RPT
> >> > Pacifica, CA
> >> > ilvey@jps.net
> >> >
> >> 
> >> 
> >
> >
> >David Ilvedson, RPT
> >Pacifica, CA
> >ilvey@jps.net
> > 
> Jon Page,   piano technician
> Harwich Port, Cape Cod, Mass.
> mailto:jonpage@mediaone.net
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net