damper "grain"

[Tony Caught]

Hi Peoples,

True, vertical/horizontal grain mainly applies to wedge damper felt. One
exception is of course the upright overdamper (birdcage).

All the dampers (except for the extreme treble) are made from endgrain or
vertical cut damper felt. (This felt may be made a little differently but
the end result is the same.)

In the case of the overdamper piano the dampers are gravity weighted, no
springs, and as such, are required to stop the string from vibrating much as
the grand piano but with less area of felt in contact with the string. Often
you will find that in fact the dampers work better because of the end grain
felts contact with the string is more positive than flat or horizontal
grain.

I am not suggesting that the underdamper pianos or grands be fitted with
endgrain felt in the treble (though it would be an improvement) as the cost
factor would be much higher. but in the bass and lower treble where you have
a choice of using horizontal or vertical cut wedge dampers, the horizontal
cut wedge is more effective in cutting the vibration of the string because
the endgrain of the felt is not packed hard and is freeier to interact with
the string.

I mention using endgrain felt in the treble as I have found that when using
the una corda and striking only two strings out of three, that the unstruck
string will vibrate sympathetically but on a different plane to the other
strings. When the damper comes into contact with the strings it may cause a
zizz as the flat horizontal felt is moved in two directions trying to stop
the vibrations on two different planes.

One could go on but I can't see it happening.

Tony Caught

----- Original Message -----
From: Bill Ballard <yardbird@pop.vermontel.net>
To: <pianotech@ptg.org>
Sent: Saturday, May 26, 2001 11:29 AM
Subject: Re: damper "grain"


> At 12:19 AM -0400 5/25/01, JIMRPT@AOL.COM wrote:
> >or another explanation is that "horizontal" felt is layered/cut parallel
with
> >the strings and "vertical" cut is cut /layered perpendicular to the
strings.
> >"Vertical" cut felts 'tend' to be of a firmer quality than does
"horizontal"
> >felt.....or have I got that backwards? :-)
>
> As I understand it, vertical/horizontal grain mainly applies to wedge
> damper felt. The strips for the wedge felts are all cut from the the
> large sheet whose layers are of course horizontal. Vertical damper
> felt is made by turning these strips 90* before cutting the wedges.
> So imagine your damper wedges: vertically cut has the layers of felt
> perpendicular to the string, horizontal parallel to the string. As
> you can imagine, the strings easily wear notches (ledges) into
> vertical damper felt, whereas wedges cut into horizontal grain tend
> to make more noise when being lifted out from between the strings.
> Horizontal felt holds its shape far better than vertical which tends
> to have its layers pried apart each time it's plopped back down on
> the string. Deep Southerner that he is, Jim should be allowed his
> backwards opinions (--we wouldn't have you any other way, Jim) <g>.
>
> Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "If we see you SMOKING we will assume that you are on fire and will
> take appropriate measures"
>      ...........Sign in a Music Dept. Hallway
> +++++++++++++++++++++