bowing keyframe

[Jon Page]

At 11:26 PM 10/09/2000 -0700, you wrote:
>on 10/9/00 8:22 PM, Jon Page at jonpage@mediaone.net wrote:
>The cut is perpendicular to the frame right?

Yes, front to back.

>What is a long tempered lathe, is it something to put inside the diagnal
>cut?

A long wedge to mated to a slightly tapered kerf.

>  In what instance is veneer needed as opposed to the cut only?
>Thanks,
>E.

If the weight of the frame does not straighten it out. The veneer needs to be
a few thousandths wider than the kerf in order to force the rail to flex.

A shims inserted into cuts made on the left side of this curve 
<  )  >  will cause
the piece to this  <  I  >  .   A few cuts may be required to produce this and
a tapered cut/wedge will be needed if a straight cut does not adequately 
reduce the bow.

Take your time,

Jon Page,   piano technician
Harwich Port, Cape Cod, Mass.
mailto:jonpage@mediaone.net
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> > By making a saw cut on the concave side about one third the thickness
> > of the rail, a piece of veneer can be inserted into the kerf to 
> straighten it
> > out. Also a tapered cut could be made and a long tapered lathe could be
> > inserted
> > to fine tune the degree of stress placed on that side, then trim the insert
> > flush to the
> > edges, only a dab of glue is needed on one side in the event future
> > adjustments
> > are needed.  I think early Yamahas had this feature in the front rail.
> >
> > Regards,
> >
> > Jon Page