Hi David, The test that I use is as follows, hold shank and flange horizontal, the flange should NOT fall under it's own weight, add the flange screw and the flange will fall in a smooth but steady manner. Comes out to four swings. So much energy is absorbed in the centre pin/flange bushing, so why are we so suprised when we change a centre pin and find the tone changes so much. Not too long ago I changed a centre pin for what I thought was one weak note on a Yamaha CF the tone came back with such force that I ended up changing all the pins in the killer octave. WOW what a diffference. The tone thickened out and became quite focused. It was an eye opener to measure the changes in sustain time of the harmonics. For about a year I have been removing a few hammers to test for friction of centre pins prior to voicing, and I feel it has made a big difference to the quality of jobs that I have been doing. Depending on money I at least do the critical areas, killer octave and bass/tenor break. Start checking I'm sure you will be suprised. Regards Roger At 08:56 PM 6/3/99 -0700, you wrote: >Roger, > >Yes, yes, yes...now what kind pinning friction do you go for. If >I'm using a swingtest I like 5 to 6. Rick Baldassin is really in >to tighter pinning claiming the same things you are talking >about. Firmer pinning means a more controlled attack on the >string i.e. less wobble. Obviously if one side is looser than >the other you will get wobbly but if both sides are to loose >you'll get wobble. > >David Ilvedson, RPT > >Date sent: Thu, 03 Jun 1999 19:08:26 >To: pianotech@ptg.org >From: Roger Jolly <baldyam@sk.sympatico.ca> >Subject: Re: Why? >Send reply to: pianotech@ptg.org > >> Hi Richard, >> I just knew some one would pick up on that statement, I'm >> smiling. >> If you have had the opportunity to study slow motion films of a travelling >> hammer you will notice several things, 1. The shank starts to bend before >> the hammer starts to move. 2. the hammer does not travel straight to the >> string but tends to wobble like a drunken sailor in flight. This wobble is >> far more pronounced on the angled hammers. >> I have just completed a test on a Yamaha U1 about 20 years old that was >> showing the phasing problem at the bass tenor break. Hammers were well >> traveled and nicely mated to the strings as well as evenly voiced. Both non >> speaking lengths of the strings were braided to remove this item from the >> equasion, the strings were seated to the bridges, and the bridge pins were >> lightly tapped to eliminate false beats. >> Problem was still there, and I had duplicated John Woodrow's problem. I >> then changed the centre pins, Making sure that about same amount of >> friction was on each side of the flange yoke. Yureka!!! the problem >> disappeared. >> I think what is happening, is that with a slightly loose pin the flight of >> the hammer is much more erratic, causing it to strike one string before the >> other, therefore giving the phasing effect. >> I change a lot of centre pins in the killer octave region of grands prior >> to voicing, and can hear the changes in harmonic structure long before the >> centre pin starts to give the classic audiable click. Down at the >> bass/tenor break there is so much going on sound wise, that I have never >> previously thought to check. >> Another thought for the reason on noticing it more on angled hammers is >> that the weight not evenly distributed down the centre line of the shank, >> adding to the wobbly flight pattern. >> Hope this sheds some light on your question. >> regards Roger >> >> >> >> >> >> At 11:09 AM 5/9/99 +0200, you wrote: >> > >> > >> >Roger Jolly wrote: >> > >> >> >> >> Similar instability can be noticed at the bass/tenor break, with the >> >> addition of phasing due to the critical nature of angled hammers. >> >> I'm sure others will add more reasons, but I would think this is the >> >> primary cause. >> >> Regards roger >> > >> >I'd like to hear more about this phasing in relation to angled hammers.. >> > >> >Richard Brekne >> >Sydneskleiven 1 >> >5010 Bergen, Norway >> > >> >E-mail Richard Brekne >> >Richard Brekne Website >> > >> > >> >> >> >> >> >> At 05:41 PM 5/8/99 -0400, you wrote: >> >> >I am wondering who can provide a definitive answer to the question of why >> >> most >> >> >pianos seem to go out of tune the most at the treble break. I have heard >> >> >several versions of answers, and would like to hear from the best. I am >> >> new to >> >> >the List, and inquiring minds just have to know! Clark Sprague >> Greenwich, >> >> >Ohio >> >> > >> >> > >> >> Roger Jolly >> >> Balwin Yamaha Piano Centres. >> >> Saskatoon/Regina. >> >> Canada. >> > >> >Attachment Converted: "c:\eudora\attach\ReWhy.htm" >> > >> Roger Jolly >> Balwin Yamaha Piano Centres. >> Saskatoon/Regina. >> Canada. >> > > >David Ilvedson, RPT >Pacifica, CA >ilvey@jps.net > Roger Jolly Balwin Yamaha Piano Centres. Saskatoon/Regina. Canada.
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