[CAUT] Servicing guide rail bushings

[Jim Busby]

Fred,

I totally agree. Just watch those that are "centered" flop and wiggle all over as the come up. That's why Steinway calls the bottom bend the "pressure bend". I like to think of it as a "control" bend. Most other manufacturers pooh pooh the idea though.

Best,
Jim

________________________________________
From: caut-bounces at ptg.org [caut-bounces at ptg.org] On Behalf Of Fred Sturm [fssturm at unm.edu]
Sent: Saturday, November 21, 2009 2:28 PM
To: caut at ptg.org
Subject: Re: [CAUT] Servicing guide rail bushings

I'll just mention again that I agree with Steinway practice to lean
the wire on the bushing, not to center it in the hole. I think you get
better damping because of the support of the wire against the bushing
cloth. It has to be carefully done: just the right amount of lean, not
enough to cause drag.
        The chatter of the damper head wobbling is not just indicative of
what is going to happen when it contacts the strings (it will bounce
and vibrate for quite a while), but it also feels bad at the key.
        Seems to me it would be quite possible to apply water and alcohol, or
VSProfelt, to the bushing cloth with a long flex nozzle. Worth
experimenting on one or two. I haven't done it, but why not try?
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu

On Nov 21, 2009, at 1:30 PM, Stan Kroeker wrote:

> Dear Colleagues,
>
> Am regretting not replacing damper guiderail bushings on a recent
> Steinway (1976 B) parts retrofit.  The new damper action installed
> smoothly and required only minimal re-bending of damper wires.
> However, in spite of careful attention to proper alignment and
> seating of bichord and trichord damper wedges, I can't seem to
> eradicate an 'oink' together with longer-than-satisfactory 'ringing-
> on' of most dampers in this part of the scale.
>
> There is actually quite a bit of free play in the guiderail
> bushings ... you can see the damper head wobble when the key is
> struck.  Am kicking myself for neglecting this important interface
> but, short of rebushing the rails, has anyone had success with
> moistening the bushings in hopes of swelling them back to acceptable
> tolerance?  I sometimes do that with moderately compressed
> keybushings ... would it work on these as well?  If so, would you
> mind sharing the procedure?
>
> Thanks and best regards from the Canadian prairie!
>
> Stan Kroeker, RPT