Graphited bushings

[Jon Page]

At 02:02 PM 2/13/2002 -0600, you wrote:
>List,
>I had an appointment this morning to voice a Kawai grand for a new 
>customer, a teacher.  She also asked me to fix a "ringer", damper not 
>seating reliably.  Actually, there was a whole bunch of dampers that would 
>seat on a hard staccato blow, but on a gentle release would not come all 
>the way down.  I pulled one out, and found a black deposit on the wire 
>(where it should have been polished from the bushing), and a pile of 
>graphite powder on the guide rail around the bushing.  Yes, she remebers 
>now, a tuner had lubricated the sticky dampers for her several years ago...
>
>So here's my question - I know I'll have to remove the dampers and the 
>guide rail to fix this problem.  Obviously, I'll polish the damper 
>wires.  Can I clean the graphite out of the bushings, say with naptha and 
>a pipe cleaner, or should I just go ahead and re-bush?  The bushings don't 
>seem to have any excess play in them, so I'd like to save her some money 
>by just cleaning and lubing, but not if this is going to come back and 
>bite me in the butt in a couple of years.  What do you think?
>thanks,
>Mike

I would opt to remove the bushings as well to get rid of the cascading 
graphite unless they vac off well and the holes can be eased.
I made a bushing easing iron from a bridge pin and 1/4" brass stock for my 
Key Bushing Iron.

Polish the wires and fine tune the bends so the wire does not exert side 
pressure on the bushing and the dampers travel straight.

Trim the felt to just even with the bottom of the unisons on the trichords. 
For the longer felts, I cut them midway with center pin nippers
thereby making two 1/2" felts out of one 1" felt.  Clean the wedge felt 
with a Dremel Tool and small wire wheel.

I usually start by placing a straight edge against the side of the damper 
head and sighting along the wire to see if they are parallel.
Once the upper leg of the wire is parallel, insert it into the bushing but 
leave the felt just over the strings. Place a small square under
the rail against the wire. Look at the head to see if it is centered over 
the unison, adjust the bend at the head to achieve this.
Recheck alignment with straight edge, replace the damper, square the wire, 
bend wire for the lower leg to align with the hole in the
top flange. Now your damper is as fast as it can be, no drag.

Reusing the old felt can be a problem if the impressions in the felt do not 
realign. A minor attempt at resurfacing may avert ringing.

Don't rush,


Regards,

Jon Page,   piano technician
Harwich Port, Cape Cod, Mass.
mailto:jonpage@attbi.com
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