pianoman wrote: > > ---------- > > From: DGPEAKE@aol.com > > To: pianotech@ptg.org > > Subject: Re: glueing controversy > > Date: Thursday, September 18, 1997 7:07 PM > > > > I never turn key pins. I have found it comes to haunt me because I later > > have to make another service call to un-turn the key because it hangs up > on > > the pin. I would rather do the job right and rebush the keys. > > > > Dave Peake, RPT > > Portland, OR > Dear Dave and others, > If the pins were not made to turn to tighten up the bushing why aren't they > round rather than oval? > James Grebe > pianoman@inlink.com James, They are oval to increase the bearing surface area. Round pins would wear the bushing felt at a much faster rate than do the oval pins because of the increased contact pressures. This is basically what you get as you rotate the so-called oval pins--many of these pins are not truly oval. As the surface area decreases, contact pressure increases and the wear rate increases. Once the felt bushing is gone, the pin starts in on the wood. --ddf
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