Tuning Hammer and Technique for Novice

[Bill Ballard]

At 4:54 PM -0500 6/16/02, SUSAN P SWEARINGEN wrote:
>Another complaint I have heard is that people don't want to have to 
>learn two hammer techniques since >the impact hammer is not suitable 
>to grands, only to verticals.  I felt the same way until I had 
>Mike >Swendsen of Canada make me a T-impact hammer for grands.  This 
>hammer works beautifully and Mike >did a wonderful job in designing 
>it.  Yes, you have to carry two different hammers in your kit, but 
>that >hasn't been an issue at all for me.

The fling which your fingers give the the impact centrifuge is simply 
oriented to a different plane by the wrist, moving from vertical to 
grand. The arm, from the wrist up, is generally not involved in the 
generation of force being thrown into the system, so it can be where 
ever it (and the wrist) will feel most comfortable. Thanks to the 
efficiency of the system, the arm and wrist can be comfortable and 
let the finders do all the work.

In practice, the extent to which this is workable is a matter of 
tuning pin torque. The impact approach is wonderful at being able to 
bounce a blow against the corners of the tuning pin and avoid, in the 
process, any twisting or bending of the pin. These are the aspects of 
the mechanics of tuning which degrade the accuracy required by the 
stability of the tuning. Impacting minimizes them.

However, another aspect of the tuning's mechanics is where the tuning 
pin torque sits, in the range between mushy to noticeably two-phased, 
through tight-gripped to snapping. The fling of impacting is nearly 
useless to gage once the pinblock grip falls below that threshold 
amount which overcomes the block's grip on the deep end of the pin. 
This is generally around 50-60 "/#. At higher levels of pin torque, 
the amount of torque surplus to the threshold level, which in the 
non-impact, firm-gripped approach is simply thrown into pin twisting 
and bending. Not only is that a potential liability, it's also a 
waste of energy.

In the impact approach, the process of overcoming the pin twist is 
still there, only this time instantaneous (or at least faster than 
human perception). The immediate amount of force required to overcome 
the block's friction grip is quickly applied, and the surplus goes 
directly to the turning the pin.

The real challenge in learning the impact approach is how the results 
change as this point of "break-free" droops lower and lower. 
Remember, the hand has contact only when it's throwing the handle, 
and not at the point of impact. So the hand has no idea which that 
"break-free" amount is, which is spent up front, and as a result, the 
proportions of the "entry fee" and the remainder which actually does 
the work. As the pin torque continues to droop lower, tuning gets to 
be more and more like striding across ice in ball-bearing boots. Lots 
of unexpected motion.

Not that I especially like tow-torque tuning, but some of our most 
stable pianos have surprisingly relaxed pinblock grip.

Look in the 2-3/91 PTJ for an article on the coordination of string 
and tuning pin friction in the mechanics of tuning. (By me.) The 
energy we put into the system is actually supplied to the tuning pin 
friction with the hope that the surplus will overcome the string 
friction, with enough remaining from that transaction to move the 
string the desired amount. Impacting makes sure that extra amounts of 
force don't get get stored (or more likely, wasted)in the springiness 
of the pin and string. But you forfeit that direct contact with the 
pin which informs you of the pinblock's grip.

Bill Ballard RPT
NH Chapter, P.T.G.

"I'll play it and tell you what it is later...."
     ...........Miles Davis
+++++++++++++++++++++