<html> 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:           <x-tab>       </x-tab>"Paul" <tunenbww@clear.lakes.com> >To:             <x-tab>       </x-tab><pianotech@ptg.org> >Subject:        <x-tab>       </x-tab>Re: Bedding Blues >Date sent:      <x-tab>       </x-tab>Wed, 9 Feb 2000 13:34:56 -0600 >Send reply to:  <x-tab>       </x-tab>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 > <div>Jon Page,   piano technician</div> <div>Harwich Port, Cape Cod, Mass.</div> <div><a href="mailto:jonpage@mediaone.net" EUDORA=AUTOURL>mailto:jonpage@mediaone.net</a></div> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ </html>