Tuning Hammer Technique and Staibilty Question

[pmc033 at earthlink.net]

Hi, Robert:
    Here's my $.02.  The secret to accurate tuning is to be able to make very small movements of the tuning pin in the block, in all kinds of pinblocks, tight or loose or anywhere in between.  You need to be able to judge whether you are just enough above the target so that when you ease the tension it drops just to the target pitch- and not below.  The pin should have a very slight amount of "reverse torque" so that the string tends to stay at the target pitch.  You want to balance that torque against the pull of the string.  I will admit here that this is my technique that I have developed over the many years I've been tuning.  
    My observation of new tuners is that they haven't mastered the technique of making small moves of the pin in the pinblock.   New tuners tend to make larger movements than necessary, and tend to put too much reverse twist on the pin (read: bending the pin).  The trick is to "test" the pin by moving the tuning lever a little bit up and down, noting whether the string tends to stay at the target pitch.  Practice doing unisons and see if the beats speed up equally on either side of pitch (sharp and flat) while you move the pin a little in either direction.  The string should tend to stay at the correct pitch.  Pounding the string down to pitch should not be necessary, and often tends to make the string go sharp later.  Try to limit the movement of the pin as soon as you feel it move in the block.  I try to put some torque on the pin enough initially so that a little bit more movement turns the pin.  You want to break the static friction on the pin, but not allow the pin to move too far.  Dynamic friction is less than static friction.  Once the pin moves, it will tend to be easier to turn the pin.  Breaking it loose, and keeping it from going too far is the trick.  An impact hammer helps (on uprights) because it allows you to do this easily.  Just enough of an impact to turn the pin a little is what you want.  I don't use an impact hammer- I have my own techniques- but I would recommend one for a new tuner.  It took me many years to perfect this, so don't be discouraged if you don't immediately "get it".  You will have to blaze your own trail, so to speak.  My suggestions here are only a guide, some hints along the way.  Just practice those unisons!  
    Also, remember that there is some friction of the wire over the bearing points.  Some pianos have a lot, some have almost none (Steinway uprights).  If the pitch doesn't change right away when you turn the pin, you have friction that is preventing the sliding of the string.  The understring felt is often the source of friction here, and you can put some protek lubricant on the string to help with this.  Just don't go hog wild and allow the protek near the tuning pin.  I use a hypo oiler and put the tip of the oiler along the strings in the felted area.  Just don't use any petroleum based lube here (WD-40).  
    If there is too little friction, the SLIGHTEST movement of the pin is going to affect the pitch.  These are a challenge, and require careful handling.  Stability is difficult to achieve, but with experience it can be done.
    Another trick is to use the natural "flagpoling" of the pin to put "reverse tension" on the string.  On uprights, a slight nudge of the pin in the direction of the string will lower the tension, and pull the string into the target pitch.  Kind of like pulling the arm on a "one eyed bandit".  Key here is: A LITTLE NUDGE- not enough to bend the pin.  
    Try to keep the handle of your tuning hammer parallel to the string.  IOn grands, a little nudge of the tuning hammer in a downwards manner will pull the string into the target pitch.  
    I have used an Accutuner since I started in 1988.  It's instant response has helped me to find the most reliable techniques to set the pins.  I can see immediately whether the string is going to stay there when I give it a good blow.  
    What I would say, in regards to "beats" and how much higher you need to be from your target pitch, is that you need to be aware of how much torque is needed to break the friction.  If your pins are tight, you need more torque.  And you need to be extra careful not to allow the pin to twist too far.  If your pins are on the loose side, you will need less torque to break it loose.  Tight pins are going to make more "beats" before they break loose (assuming you are doing unisons).  If you get a feel for how many beats it takes to move the pin, you can judge how many beats you need to have above the pitch so that when you put your "reverse twist" into the pin, it will end up on pitch and not move further.  With tight pins, you may have to go a little "flat", moving the pin past the target pitch on the flat side, so that the torque on the pin drags the string up again into pitch when you nudge it sharp.  Let the pin itself do the stabilizing for you.  It isn't enough for you to have the string at pitch- you must create the conditions by which it will STAY there when you remove the tuning hammer and give it a test blow.  Balancing the torque on the pin and the slight bending of the pin towards the speaking length against the tension of the string is the goal here.  
   The best way to learn is to try different ideas and techniques and see what works for you.
    I hope this helps.
    Paul McCloud
    inSane Diego


----- Original Message ----- 
From: Robert Finley 
To: pianotech at ptg.org
Sent: 03/29/2006 10:07:31 PM 
Subject: Tuning Hammer Technique and Staibilty Question


I would like to ask a question about how the tuning hammer should be used to achieve a stable and accurate tuning. I understand that one has to turn the tuning pin with the hammer so that the string is slightly above pitch, and then ease it back down into position, presumably to eliminate any self-twisting of the pin that could occur afterwards, causing the string to go out of tune. I guess this is because the tuning pin is flexible and the twisting at the bottom of the pin where it is seated in the pin block lags the twisting at the top of the pin over which the tuning hammer is placed. 

My question is, how much should one tune the string above pitch before easing the pin back down? Should it be a few cents, cycles or what? I find it interesting that the tuning pin is that flexible because it seems to be made of rigid steel. I would expect the twisting effect of something that rigid to be minute, but enough to cause a string to go out of tune if the incorrect hammer technique is used. I have found that on my own piano, I can turn the tuning hammer a noticeable amount without a change in pitch, until I reach a point where it does start to change. 

Thank you for your advice. 

Robert Finley
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