THUD

[John D. Chapman]

Dale,
I did look for marks on the hammer shanks to see if that could be it, but
will try your idea of inserting something.
John

On Sun, 3 Dec 2000, Ward & Probst wrote:

> John,
> Really reaching here but have you checked top of hammer shank to lower edge
> of pinblock clearance? You can insert a thin piece of material between them
> to see if it makes the situation worse for a quick check. Like I said, it's
> a reach but I have had it once before.
> Best,
> Dale
> Dale Probst, RPT
> Member, TEAM2001
> PTG Annual Convention
> Reno, NV --July 11-15, 2001
> email: wardprobst@cst.net
> (940)691-3682 voice
> (940) 691-6843 fax
> TEAM2001 website: http://www.ptg.org/conv.htm
> 
> 
> 
> -----Original Message-----
> From: owner-caut@ptg.org [mailto:owner-caut@ptg.org]On Behalf Of John D.
> Chapman
> Sent: Saturday, December 02, 2000 7:26 PM
> To: caut@ptg.org
> Subject: Re: THUD
> 
> 
> Remember THUD?
> Here is the history.  I had not seen this piano until last month.
> While tuning I noticed that notes 50, 51, 52, and 53 (top four notes in
> agraff section,  just below the treble break) had an unpleasant
> knock/slap sound, the same percussive knock which is in the background of
> all piano tone, but in notes 50-53 it dominates the tone.  These are the
> four notes between A440 and the treble break.  The orchestra conductor
> asked me if I had noticed those four notes, as did the pianist, so I knew
> it wasn't just my imagination. I have checked it out both upstage and back
> stage (wood floors), and back at the dealership (concrete floor).
>         Here is what we have done so far:
> 1.  checked hammers for loose glue joint, flange pinning, and screw
> tightness,
> 2.  visually checked the action frame joints between notes #53 & #54,
> 3.  checked the wippens for sufficient felt at the front to keep the
> jack from slamming into the rep lever,
> 4.  checked key frame bedding, front, back, and glides, with and without
> damper pedal, and with and without shift pedal,
> 5.  pressed down the back key frame with a long screwdriver to see if it
> was slapping up against the dag,
> 6.  played notes with dampers held all the way up by hand and by pedal,
> 7.  moved the action in and out to see if the tone improved,
> 8.  switched some hammers from the octave below to see if it could be the
> hammers,
> 9.  switched some whippins from the octave below to see if it coulb be the
> whippins,
> 10.  seated the strings,
> 11.  applied firm pressure on the bridge cap at the end of the section to
> see if there was a loose glue joint between cap and bridge body,
> 12.  checked for clearance between the bridge and the plate,
> 13.  checked for loose ribs,
> 14.  checked for clearance between nose and bell bolts and soundboard,
> 15.  checked that the bell bolt nut which was one turn past finger tight,
> 16.  checked for foreign object lodged between soundboard and frame, and
> between soundboard and plate,
> 17.  tightened the end screws of the diagonal plate bar, which could be
> turned another half turn to snug,
> 18.  checked key leads and underlever leads,
> 19.  checked the key bed with a straightedge front to back.  I found that
> the board just beyond the board on which the balance rail glides rest was
> high.  Chalked it where it passes under the front to back board of the key
> frame which is just under notes 50-53 and found that is was just barely
> touching. Sanded key frame there until there was adequate clearance.
> Playing the note by pushing up on the whippin from underneath with my
> finger without moving the key still produces the THUD, so I guess that
> eliminates the keyframe anyway.
> 
> None of this has changed the THUD.
> What have I missed?
> Why these four consecutive notes  with no sign of the problem above or
> below them?
> 
> John Chapman RPT
> Wake Forest University
> Winston-Salem NC
> 
> 
>