Repetition Revisited

[Roger Jolly]

Hi Lance,
              Plenty of after touch can be part of the problem with high
checking. Let off, drop, after touch and checking height are all inter
active.  A penny is 0.030" or more, ( I'm guessing) for well regulated
concert grands I prefer to be in the 0.015" to 0.020" range.  To get there,
all action components have to be healthy. Good pinning and consistent
friction.

A rule of thumb for checking height. A Jollyisum,  Divide the check length
into thirds, with the hammer at the desired height, the centre line of the
shank should line up with the top one third point of the check.
With the radius of the tail that I previously described it works every
time. The tail length below the shank centre line should be about 3/4" but
no more than  7/8"
Over centreing hammers, due to many reshaping jobs, is a whole new can of
worms.
Another check for you, measure the bore distance and see how far off spec,
could be a double wammy.  Reshaped hammers and poorly bored to begin with.

Regards Roger
 



At 10:47 PM 07/08/00 -0500, you wrote:
>Thanks Roger, I have plenty of aftertouch  (more than .396 dip - I use a
>penny with a hole drilled in it to get close, then feel for consistency)
>since these concert gymnists seem to like plenty.  I will get to work on
>your ideas and look forward to the article!  Thanks.
>
>P.S.  How do you decide what height new backchecks should be installed?  If
>originals were the big Steinway size and I am installing Renner(smaller).
>Often times pianos have been tampered with so much, I'm not sure what
>criteria to use.  I was told  after regulating, 1 1/2mm below the tail after
>drop but before aftertouch.
>Lance Lafargue, RPT
>Mandeville, LA
>New Orleans Chapter
>lafargue@iamerica.net
>
>
>-----Original Message-----
>From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf
>Of Roger Jolly
>Sent: Monday, August 07, 2000 12:18 PM
>To: pianotech@ptg.org
>Subject: Re: Repetition Revisited
>
>
>Hi Lance,
>              Take a set of compasses, set them at 2 1/2'' to 2 5/8", place
>the pencil lead at the end of the molding at the bore hole,  set the point
>into the centre line of the shank, and scribe an arc on the tail.
>This will confirm if you have a tail geometry problem.  Gina and I have
>some photo's coming out in the Journal along with an explaination of tail
>and check geometry.
>Bill Spurlock's tailing jig will solve this problem for you.
>A reasonable rule of thumb to work from. Tailing arc, is half the radius of
>the centre to rear of the molding length. Most pianos fall in the 5" to 5
>1/4" range
>
>The Rake of the checks for Steinway I think is 22 degrees. Have to dig out
>some notes to confirm.
>
>What do you have for after touch?
>
>Regards Roger
>
>
>At 08:16 AM 07/08/00 -0500, you wrote:
>>Hey folks,
>>I had a problem with repetition on a Steinway concert grand last week that
>>has occurred before and hoped someone could help.
>>
>>I was working for an International Piano Competition in which some very
>good
>>players required lightning fast repetition and for the most part, I
>achieved
>>it.  As the week wore on and the rep springs were repeatedly tightened and
>>it was pounded on for 14 hours each day, I noticed a problem I've seen
>>before.
>>
>>This piano has Steinway hammers on it, but not factory original hanging.
>>1985...   After the key is depressed and only partially raised (1/8 inch?)
>>for the next blow, upon the next key depression the hammer gets wedged
>>against the backcheck and blocks.  It doesn't happen every time.  In other
>>words the hammer has let off and while the key is still almost completely
>>depressed the hammer tail is not against the upper part of the backcheck
>>like normal, but much lower and is trapped making the key feel almost like
>>the hammer is blocked against the string.
>>
>>Repetition springs are tight with plenty of bounce.  Key height is close to
>>spec, hammer line, dip, etc., all normal.  It doesn't seem like the rep
>>lever would allow the hammer to go that low and get trapped.  I have seen
>>this on another piano, older vintage (late 60's or 70's).  **I should also
>>add that I have not been able to get close checking without the tail
>rubbing
>>on the backcheck on hard blows and I also could not get good checking at
>all
>>on soft blows with the springs on the strong side.  I experimented with
>>backcheck angle to no avail.  HELP!!  Thanks in advance.
>>
>>Lance Lafargue, RPT
>>Mandeville, LA
>>New Orleans Chapter
>>lafargue@iamerica.net
>>
>Roger Jolly
>Saskatoon, Canada.
>306-665-0213
>Fax 652-0505
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505