The idea is to just have it *barely* leaning against the bushing. This creates stability of the damper head and helps keep the wire from vibrating. Here's a clip from Mario Igrec's "Pianos Inside Out":
http://www.pianosinsideout.com/regbig.pdfTo Center the Wire in the Bushing or Not?
If the damper wire bears against the bushing with significant force,
the bushing will wear out prematurely. The logical conclusion is to
adjust the wire to be centered perfectly in the bushing. However,
the damper is actually more effective if the wire is slightly off center.
Here's why.
Let's look at a single bass string. Although the hammer excites
the string to vibrate in a vertical plane, the vibrations change direction, and soon the string is vibrating in all directions. When the
damper falls on the string, it pushes the string down, causing the
vertical vibrations to quickly subside. Vibrations around the horizontal plane, however, cause the damper head to move left-right.
You can observe this when loudly playing low-bass notes-the
damper head flutters horizontally (side to side) when it touches the
string. By itself, the damper can't stop horizontal vibrations-that's
the job of the damper bushing.
The bushing damps horizontal excursions of the string by limiting side-to-side travel of the damper head. The tighter the bushing,
the more effective it is. However, the adjustment of the damper
wire can make the bushing even more effective. Suppose that the
string is deflected from its rest position by 1 mm to the left and
1 mm to the right.
Also suppose that the damper wire is 1 mm
thick and the opening in the bushing has a diameter of 3 mm, leaving 1 mm of room on each side of the wire. If the damper wire is in
the middle of the bushing, the string will move it equally in both
directions, for a total motion of 2 mm. But if the wire leans against,
say, the right side of the bushing, the excursion to the right will
cause almost no damper movement, whereas the excursion to the
left will bring the wire to only the middle of the hole. The total
motion will be only 1 mm, half of what it would be with the wire
centered. The degree of the lean must be very gentle or the added
friction will offset the benefits of this technique by making the
damper less effective in the vertical plane.
The lean also makes damper movement, when lifted with the
pedal, appear more precise because there is no fore/aft movement
of the damper heads
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Ryan Sowers
Olympia WA
360-705-4160
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Original Message:
Sent: 10-16-2021 12:30
From: Jon Page
Subject: Steinway Damper Guide Rail - when to rebush?
I don't lean the wire against the side of the bushing. Why induce friction? The new felt is glued on (hot hide) and allowed the dry prior to fitting the set.
I hold a small square against the guide rail and wire to have the wire perpendicular thru the hole. Then I center the head over the unison.
With the wire still secured to the square, I have the wire entering the top flange such that there is not twisting to the underlever.
The dampers travel straight up and down. Ed Foote's Wire Wizard makes bending a cinch, thanks Ed !
To make wire insertion into the top flange easier, ream the hole around 5 thousandths larger than the diameter of the wire.
Cloth that is properly sized will not leave a seam as such. But I do place the 'break' at either the front or back since the damper head will be
weighing on the wire towards the offset. On double-bushings I place the breaks opposite each other.
PS: Always rebush the guide rail. It will be quieter and support the wire better.
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Regards,
Jon Page
mailto:jonpage@comcast.net
http://www.pianocapecod.com
Original Message:
Sent: 10-16-2021 08:38
From: Mark Dierauf
Subject: Steinway Damper Guide Rail - when to rebush?
If you tear the cloth accurately, there are no seams <g>
Seriously though, Steinway recommends that bass damper wires bear "slightly" towards the treble and treble wires "slightly" to the bass, so I put the seams fore & aft.
Ryan -
I'd think that just replacing the damper felts would entail some remedial wire bending, and I'd rather have polished wires rubbing against clean, well sized cloth. It's the little things like this that add up to a better experience for the pianist. Removal, de-bushing, cleaning, rebushing and reinstalling typically only take an hour or so, once the dampers are out.
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Mark Dierauf
Concord NH
603-225-4652
Original Message:
Sent: 10-16-2021 07:54
From: Robert Anderson
Subject: Steinway Damper Guide Rail - when to rebush?
How do you orient the seams, Mark?
Bob Anderson
Tucson, AZ
Original Message:
Sent: 10/15/2021 7:58:00 AM
From: Mark Dierauf
Subject: RE: Steinway Damper Guide Rail - when to rebush?
Rebush. Drill out the originals (3/16" bit, I believe, but check first) and lightly chamfer the empty holes top & bottom. Cut (or rather, tear) a dozen or so short pies of bushing cloth of the correct width. Clamp the rail to the bench and run all the strips through and cut them all at once. This goes pretty quickly. Do NOT use any glue – the chamfering will hold the cloth in place quite securely. After all the holes are bushed insert #7 bridge pins and size overnight with your favorite sizing agent (I use isopropyl alcohol, but profelt also works fine). This typically leaves the bushing ready to go, with no further easing required.
Original Message:
Sent: 10/14/2021 1:53:00 PM
From: Ryan Sowers
Subject: Steinway Damper Guide Rail - when to rebush?
Hello Pianotech friends,
In the past, I have been fairly tolerant of damper guide rail bushings if I'm replacing damper felt. On the few jobs I've done, the guide rail felts have looked pretty good. My understanding is that Steinway guide rail bushings are purposefully a little loose with the concept being that the wire will gently ride along one side of the bushing for stability.
"To rebush or NOT rebush. THAT is the question".
For those of you with more experience with grand damper replacement, how do you decide when to replace the felt?
My concern is that rebushing will not only cost the client a few more hundred dollars for the job, but also create a lot more wire bending for me when reinstalling the dampers. If the whole damper system is being replaced it makes sense to rebush the rail, but what about just a basic damper felt replacement?
Thanks, as always!
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Ryan Sowers - Puget Sound Chapter #985
Olympia WA
360-705-4160
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