Yamaha P1 backrail "cloth"

[David ilvedson]

> Date:          Sat, 07 Sep 1996 16:16:49 -0700 (mst)
> From:          Jim <pianotoo@IMAP2.ASU.EDU>
> Subject:       Re: Yamaha P1 backrail "cloth"
> To:            Wimblees@aol.com
> Cc:            pianotech@byu.edu
> Reply-to:      pianotech@byu.edu

>
> On Sat, 7 Sep 1996 Wimblees@aol.com wrote:
>
> > Dear List:
> >
> > Today I ran accross a problem I have never witnessed. I tuned a 35 - 40 year
> > old Yamaha P1 with very bad lost motion. I started adjusting the capstans,
> > but the first key I did wound up blocking the hammer against the string. I
> > then noticed that under the back of the  keys, where the back rail cloth is
> > supposed to be, was some gooie (sp) material, with the consistency of peanut
> > butter, only a little more solid. I could scape this stuff off the wood with
> > my fingers.  My recommendation to the customer was to replace this stuff with
> > regular back rail cloth.
> >
> > First of all, can anyone tell me what this stuff is. And second, does anyone
> > know what thickness of cloth I need to use.
> >
> > Willem Blees  RPT
> > St. Louis
> >
>
> Dear Wim:
>
> The gooey material may have been melted sponge rubber which was tried by
> various manufacturers back in those days.
>
> If you haven't already run up all of the capstans, a good procedure is to
> select a backrail cloth which raises the majority of the capstans to the
> point of minimum lost motion, as long as you still will have fairly normal
> keydip.  This will minimize your regulation work and is probably as close
> to the original as you can get.  Be sure that you will still have suffi-
> cient keydip.  You wouldn't want the key overlip to clack on the keyslip,
> and you wouldn't want the back of the sharps keysticks to be limited
> by the normal position of the nameboard or keystop rail.
>
> Jim Coleman, Sr.

William,

I ran across the same thing a number of years ago.  I replaced
with backrail cloth and when I was done the keys were perfectly
level!!!!
David ilvedson, RPT
Pacifica, CA