---------- > From: Ron Nossaman <nossaman@SOUTHWIND.NET> > To: pianotech@ptg.org > Subject: Re: more heresy > Date: Tuesday, September 16, 1997 12:01 PM > > > >Is there a formula to compute this down bearing? I am looking for > >one that computes the down bearing of a single string, given its > >tension and deflection. > >Richard Moody > > > > > > > > I posted this in July, didn't you guys get one of these? Sorry Ron I completely forgot about your charts. However not having either downbearing guage, I am stuck there. I guess the angle could be figured if the string cnfiguration over the bridge could be viewed as two right triangles if you knew the length of the opposite and adjacent sides. Actually opposite and hyp could be counsidered the same since the lift of the string represents the adj and is so small. But I wonder how much adj changes per say 10 mm length as compared to 100 mm of length. Looks like it gets in to some trig, like how long a base do you need to get an adj of 1/8" at 1 degrees theta. But is seems like it could be put in a chart kind of like what you presented.Or better a spread sheet. Still seems if you need to know how much force does it take to lift a wire under 180 lbs of tension 1/8" that would be a vector problem. The right triangle is there, but I havn't been able to figure it out. There is also the length of the wire increasing because it is elastic. Richard Moødy. > (0248) > > Bubble reading to Degrees to Bearing Load conversion > for Lowell and Baldwin downbearing gauges. > > Measure bubble offset difference between string segments > on both sides of the bridge. Look up angle and bearing factor > on appropriate chart. For bearing load in pounds, multiply > bearing factor times string tension. > > Ron Nossaman July 27, 1997 > > Baldwin Gauge | Lowell Gauge > ------------------------------|----------------------------- > Bubble Angle Bearing | Bubble Angle Bearing > ------------------------------|----------------------------- > 0.5 0.14167 0.0025 | 0.5 0.09375 0.00164 > 1.0 0.28333 0.005 | 1.0 0.1875 0.00327 > 1.5 0.425 0.0075 | 1.5 0.28125 0.00491 > 2.0 0.56666 0.01 | 2.0 0.375 0.00655 > 2.5 0.70833 0.0125 | 2.5 0.46875 0.00818 > 3.0 0.84999 0.015 | 3.0 0.5625 0.00982 > 3.5 0.99166 0.0175 | 3.5 0.65625 0.01145 > 4.0 1.13332 0.02 | 4.0 0.75 0.01309 > 4.5 1.27499 0.0225 | 4.5 0.84375 0.01473 > 5.0 1.41665 0.025 | 5.0 0.9375 0.01636 > 5.5 1.55832 0.0275 | 5.5 1.03125 0.018 > 6.0 1.69998 0.03 | 6.0 1.125 0.01963 > 6.5 1.84165 0.0325 | 6.5 1.21875 0.02127 > 7.0 1.98331 0.035 | 7.0 1.3125 0.02291 > 7.5 2.12498 0.0375 | 7.5 1.40625 0.02454 > 8.0 2.26664 0.04 | 8.0 1.5 0.02618 > 8.5 2.40831 0.0425 | 8.5 1.59375 0.02782 > 9.0 2.54997 0.045 | 9.0 1.6875 0.02945 > 9.5 2.69164 0.0475 | 9.5 1.78125 0.03109 > 10.0 2.8333 0.05 | 10.0 1.875 0.03272 > 10.5 2.97497 0.0525 | 10.5 1.96875 0.03436 > 11.0 3.11663 0.055 | 11.0 2.0625 0.036 > 11.5 3.2583 0.0575 | 11.5 2.15625 0.03763 > 12.0 3.39996 0.06 | 12.0 2.25 0.03927 > 12.5 3.54163 0.0625 | 12.5 2.34375 0.0409 > 13.0 3.68329 0.065 | 13.0 2.4375 0.04254 > 13.5 3.82496 0.0675 | 13.5 2.53125 0.04418 > 14.0 3.96662 0.07 | 14.0 2.625 0.04581 > 14.5 4.10829 0.0725 | 14.5 2.71875 0.04745 > 15.0 4.24995 0.075 | 15.0 2.8125 0.04908 > 15.5 4.39162 0.0775 | 15.5 2.90625 0.05072 > 16.0 4.53328 0.08 | 16.0 3. 0.05235 > > > Ron Nossaman >
This PTG archive page provided courtesy of Moy Piano Service, LLC