Pianotech

Hi all,

In my personal rebuilding project, I've opted to use the original wippens (wippen assemblies) for two reasons, 1) new wippens are not in my budget at the moment, and 2) I'm getting ready to take the technical exam at convention next month, so I can use the practice in working with these old parts.  

I'm nearly finished refurbishing the wippens.  I have opted to re-pin where necessary as I prepare for regulation and action balancing with new hammers.  Nearly half of the pins/bushing on the wippen flanges measured in the 4-5 grams which is good, and the other half 1-2 grams. Repinning these loose ones with the next half size pin seemed to fix the problem after removing a slight amount of bushing felt with a fluted reamer.  The pins in both the repetition and jack are a little more complicated to measure since the repetition spring is held in place with a cord.  I can slip the top repetition portion of the spring out from under the repetition and get a gram reading on the pin/bushing friction, but removing the bottom portion of the spring from the jack is more complicated, though it's manageable once the top portion is removed. 

My question is this: since the jack pinning has little effect on the touch weight (as far as I understand), should I primarily check for too much side-to-side play and not worry so much about gram tension, or should I "bite the bullet" and get accurate readings on the jack pin friction? As a side note, not one pin that I've tested up to this point has had friction above what it should.

Thanks in advance!

And on another note, I really appreciate all the feedback and patience you have all shown me as I learn this incredibly complicated but fascinating side of pianos. I definitely could not have done this without the PTG! 

Hi Tim, 

This wippen friction is more important than you think.  You will not get good repetition without the friction and size of spring wire being proper for the action. 

I found this in a former discussion. 

In order to measure you need to remove both ends of the spring (while you do this it is good practice to clean both end of the springs and the hole and slot removing the divot on  the underside of the rep at the knuckle and lubricating hole and slot with graphite.  You have to have the parts oriented the proper direction away from the affects of gravity (on its side for the rep lever, if you are using a friction gauge).  You would be surprised but the repetition lever to post can have friction up to 7 grams when it is in higher humidity and still work fine but don't drop below the low number and your lever will not hold the knuckle to have the jack return ready to fire again. Be careful of where your spring is when you check for friction. 1-2 gr is acceptable for the jack pinning it must be free and should freely fall when you tip the wippen over towards the jack w gravity of course without the spring.

Written by Don Mannino, 8/11/2007 archived at

http://www.ptg.org/pipermail/pianotech/2007-August/209291.html

Here are my usual guidelines, with notes.  Gram measurement is made with a
spring gauge at the screw hole, except where noted.


hammer flange centers

Depends on felt quality and firmness. My usual range would be 2 - 6 grams,
depending on humidity and bushing quality. 2g during dry conditions is OK
with good bushings, but will give poor tone with spongy bushings.  If it's
raining and the bushings are not especially firm feeling, pinning at 6 grams
might be good.  Evenness from note to note is most important in this center.

whippen flange centers

4 - 6 grams

balancier center

4 - 5 grams measured at the drop screw pad (with spring detached, of
course).   This is a very tight feeling bushing when you are testing with
the center pin.

Jack should be pinned so that it falls slowly of it's own weight when the
wippen is held with the jack tender pointing up.  This give a correct amount
of friction to match the weight of the upper part of the jack, which helps
control unwanted jack bounces during fast play.

Don Mannino

Jessica, thank you very much!

Written by Don Mannino, 8/11/2007 archived at

Here are my usual guidelines, with notes.  Gram measurement is made with aspring gauge at the screw hole, except where noted.hammer flange centersDepends on felt quality and firmness. My usual range would be 2 - 6 grams,depending on humidity and bushing quality. 2g during dry conditions is OKwith good bushings, but will give poor tone with spongy bushings.  If it'sraining and the bushings are not especially firm feeling, pinning at 6 gramsmight be good.  Evenness from note to note is most important in this center.whippen flange centers4 - 6 gramsbalancier center4 - 5 grams measured at the drop screw pad (with spring detached, ofcourse).   This is a very tight feeling bushing when you are testing withthe center pin.Jack should be pinned so that it falls slowly of it's own weight when thewippen is held with the jack tender pointing up.  This give a correct amountof friction to match the weight of the upper part of the jack, which helpscontrol unwanted jack bounces during fast play.Don Mannino

Her advice is spot on. You need the jack to be loose and at the same time the replever needs to be tighter to hold up the hammer. The spring needs to be taken out of the picture. Use a dental pick to get the spring out of thess cord. Sideplay is something to worry about and may call for replacing the felt bushing. As much as possible the jack should be centered in the rep lever window which may require bending the pin. There is a tool in the Schaff catalog for that task. 

To maintain sanity do each whippen in batches of 22. Take a break . It is a good idea to mark the whips with different colors of chaulk . If you skip some mark them so you know they where okay. Another tip is to have all your repinning tools, center pins organized , good lighting, magnifier to examine bushings. I like to do one task at a time like the measuring and recording of gram values of each part, removing the center pins and recording the size after miking. The less you handle tools the better. I recently did knuckle replacement on a Samick and once I got into a rhythmn the job was more enjoyable.

Written by Don Mannino, 8/11/2007 archived at

Here are my usual guidelines, with notes.  Gram measurement is made with aspring gauge at the screw hole, except where noted.hammer flange centersDepends on felt quality and firmness. My usual range would be 2 - 6 grams,depending on humidity and bushing quality. 2g during dry conditions is OKwith good bushings, but will give poor tone with spongy bushings.  If it'sraining and the bushings are not especially firm feeling, pinning at 6 gramsmight be good.  Evenness from note to note is most important in this center.whippen flange centers4 - 6 gramsbalancier center4 - 5 grams measured at the drop screw pad (with spring detached, ofcourse).   This is a very tight feeling bushing when you are testing withthe center pin.Jack should be pinned so that it falls slowly of it's own weight when thewippen is held with the jack tender pointing up.  This give a correct amountof friction to match the weight of the upper part of the jack, which helpscontrol unwanted jack bounces during fast play.Don Mannino