Bedding Blues

Jon Page jonpage@mediaone.net
Thu, 10 Feb 2000 07:21:41 -0500


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I forgot to mention that you should only put a little glue
on one side of the wedge to tack it in place, in the event
that it becomes necessary for future adjustments.

Jon Page

At 11:02 PM 02/09/2000 -0800, you wrote:
>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
> 
Jon Page,   piano technician
Harwich Port, Cape Cod, Mass.
mailto:jonpage@mediaone.net
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