Thanks, Ron. I needed it, too! Paul Chick ----- Original Message ----- From: Ron Nossaman <RNossaman@KSCABLE.com> To: <pianotech@ptg.org> Sent: Friday, October 12, 2001 6:22 PM Subject: Re: Lowell guage > >Hi list, > > Does anyone still have the original lowell downbearing gauge > >instructions , that tell what the scale markings are supposed to be > >calibrated to? For fun I went to the Baldwin class at Sparks and the > >Baldwin people disagreed with Mr. Lowell as to the actual degrees that > >the bubble markings corresponded to. But I can't find my notes, > >soooooo............... > > > >Thanks > > > >Dale Fox > > > > Here you go Dale, Tom sent me this some time back. > > > In brief, the thousandths of an inch quantities represented by the linear > increments (division lines) on the gauge are the rise or fall (vertical > dimension) per inch of length of piano string. So, to give an example, if > your rear string length > was 3" and your gauge measurement was .009", then the difference in elevation > between the top of the bridge (a reference at zero), and the rear string > rest would be 3" x .009" or .027". Very simple math. These dimensions can > be converted to degrees of angle by multiplying 1/6 degree times the number > of division lines the bubble has crossed. Crossing six division lines would > mean 1 full degree of string angle. More simple math. To determine the lbs. > pressure > from the net downbearing measurement multiply the net bearing in thousandths > of an inch by the tension of the string. For example, a string of 200 lbs > tension, deflected by the bridge so that a net downbearing measurement of > .018" (1 degree) is created, will produce a downbearing pressure of 3.6 lbs. > (200 x .018). More simple math. Incidentally, the bridge is pushing up at > the string 3.6 lbs. at the same time the string is pushing down on the bridge, > thus creating a static equilibrium, like a depressed spring. An > understanding of trigonometry is unnecessary, but can't hurt anyone. > > > Ron N >
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