The 8 oz weight is in the shape/form of what? I believe the 8 oz weight is used as a demonstration for the amount of force to use with the testers hand? I have helped give the test a few times but I don't remember anyone dropping 8 oz. weights on the keys... David I. *********** REPLY SEPARATOR *********** On 2/12/01 at 9:06 AM romanop@attglobal.net wrote: >In the PTG tuning exam, stability is checked by dropping an eight ounce >weight from six inches above the key and then checking to see that the >pitch >has not changed. It is a considerable "whack". > >Phil Romano >Myrtle Beach, SC > > >----- Original Message ----- >From: "David Ilvedson" <ilvey@jps.net> >To: "pianotech" <pianotech@ptg.org> >Sent: Sunday, February 11, 2001 9:17 PM >Subject: Re: Whacking > > >> The PTG Tuning test has a technique to test the stability of the unison >portion of the test. Maybe someone can post that exact info. It is not >whacking in any way...Tuning stability is a combination of good hammer >technique and an adequate force to insure that a portion of the string >segments isn't excessively different than other segments. Equalizing of >the >segments is apparently not possible...Hitting the keys as hard as you can >until the note won't drift means a total lack of hammer technique. I do >not >whack anymore and my tunings stand up to concertos...The archives have lots >of stuff on this subject. >> >> David I. >> >> *********** REPLY SEPARATOR *********** >> >> On 2/11/01 at 8:18 PM Yardarm103669107@AOL.COM wrote: >> >> >Bill: >> >While the pin might be very stable, the segments of string from the >tuning >> >pin on out to the waste length are under less and less tension if the >> >pitch >> >is being changed upward; the reverse is true in pitch lowering. The >string >> >system is unstable until an equalizing force is used to attempt to >> >overcome >> >friction at terminations and get the tension to equalize. I personally >> >doubt >> >that a string system left unaltered is stable enough to leave for very >> >long. >> >On the other hand, a stiff blow which is allowed to linger rather than >> >stacato damped will go a long distance in stabilizing the string system. >> >Overhard blows can indeed destabilize the system in the reverse >direction. >> > >> >A good test of this phenomenon is to try this. The next time you have to >> >raise the pitch on a piano more than 20 cents, pick a string in the >middle >> >register and after pulling it up to where you want, take a brass punch >and >> >give the waste length of string on the other side of the bridge a tap in >> >the >> >opposite direction of the bridge pin, i.e. as if you were unseating the >> >string; you will immediately notice a drop in pitch in the singing >length >> >as >> >tension is released around the bridge. If you did not give the string a >> >stiff >> >blow to equalize out tension, then that residual unequal tension would >> >gradually detune the piano. More thoughts? Is this clear? Again, I'm not >> >advocating damaging blows (either to the piano or to self). >> >PR-J >> >> >>
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