[CAUT] Damper wire alignment (was:Underlever Felt)

Jon Page jonpage at comcast.net
Mon Aug 24 19:30:19 MDT 2009


>I still have a problem determining which way and how to bend the 
>wire for fit in the top flange...do you see something in particular 
>that tells you I need to bend the wire towards the bass?   The first 
>bend is above the top flange?

With the wire perpendicular to the guide rail and the head centered
over the unison, the unsecured top flange should be free to move
on the wire. I'm assuming the guide rail is parallel to the string plane.

One way to visualize the offset is to make a few tools.
One wire is suspended from the strings perpendicularly.
The other wire is inserted in the top flange.

This gives you the offset and the angle at which the
wire needs to enter the top flange. If you hold the damper wire
with a square against the guide rail and a sample wire
in the top flange, it does the same thing.

Many times I find it necessary to ream the top flange hole
.003 to .005" larger than the wire to insure easier assembly.

I also try to make the wire offsets parallel to the damper head,
at least the top section.  I use my 90 degree damper wire bender
for combination handle to sight this and it is also is scored
at two points for indexing the bends.

First, place the wire in the guide rail and square it off.
Center the head over the unison: remove the damper and make
the appropriate bends at the head; check that the head is parallel
to the top section of wire by holding the bending tool against the head.
Reinsert the wire in the bushing, square it off and recheck the damper
head alignment over the unison. This may take a few readjustments.

With the wire braced perpendicularly to the rail, ascertain the offset
and angle of the bottom section to the top flange hole alignment wire.
Correct the bends to allow the top wire section to remain perpendicular
to the rail while the lower section inserts freely into the top flange.

Secure the set screw. The damper should travel straight up and down
without drag.

The other school of thought is to have the wire pressing into the
guide rail bushing. This may save time on installation and assist
damping by bracing the wire but I see it as unnecessary friction
because frictionless damper motion dampens as well (if not better).

I don't want to make the damper wire up tight,
I like it free and easy. Friction is like a real  drag.
-- 

Regards,

Jon Page
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