http://ptg.org/pipermail/caut_ptg.org/1999-June/001718.html
is the article to read on the Accujust, thanks to Ron Nossaman.
I had trouble this morning accessing the link, so am posting my
saved copy to save you some aggravation. If you don't have access
to the bubble guage, THEN I'd suggest taking downbearing readings
(take them anyhow, even if you have a bubble guage)....set the
downbearing according to the proceedure below. When I checked
my SD10 my dial downbearing guage read exactly the same as the
bubble guage. So you may not need a bubble guage depending on
what guage you have. If you take the reading you can reset to
that reading, following the order Baldwin requires.
Good luck with it.
cheers,
Richard Adkins
Coe College
>>>>>>>>>>>>>>>>>>>>>>>>>>>>PRINT THIS OUT<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
1-29-1997
TS039D
PROCEDURE TO ESTABLISH PROPER DOWN BEARING OF STRINGS ON BRIDGES OF BALDWIN
GRAND PIANOS DESIGNED WITH HOLLOW VERTICAL (ACU-JUST) HITCH PINS
These conditions must exist before bearing can be established:
1.All strings associated with the treble bridge must be in place, (Bass
strings to be installed later.)
2. These strings must be tuned to A-440 pitch.
3. All strings on the treble bridge must be set at proper height on their
hitch pins to read zero (0.0) bearing at the bridge. Follow this procedure;
begin at treble end of treble bridge with note #88 and work toward bass.
Lift wire and raise tension of the strings on the first ten (10) notes,
Then raise wire and adjust tension of the next ten (10) notes and proceed on
until all wire is adjusted in this manner on the treble bridge.
Procedure for string height adjustment.
1. Become familiar with bubble gage adjustments and application as shown
with the attached illustrations,
2. With strings at normal tension, begin with strings at the bass end of
the treble bridge and work toward the middle, Set bearing values as shown
in the following chart on specified notes only. Tap the string down by
placing the tool over the hitch pin, resting on the wire, with the bubble
gage held onto proper strings with the magnet built into its base, tap the
setting tool with a small hammer to lower the string to achieve a proper
bubble gage reading. If the string is too low, raise the string, using a
coil lifter and leather or felt to protect the plate finish.
Scale SA(5'2") ST(5'8") SC(6'3'') SF10(7'0") SD10(9'0'')
Notes to be set 27-44 27-43 23-40 21-39 21-35
Bubble Deflection 1 divis. 1 divis. 1 divis. 1 divis. 1 divis.
3. After strings associated with the notes which were adjusted in the
preceding operation have been set, proceed on with notes listed in the
following charts.
Scale SA(5' 2") ST(5'8") SC(6'3'') SF10(7'0") SD10(9'0")
Notes to be set 45-53 44-53 41-53 40-53 36-53
Bubble Deflection 2 divis. 2 divis. 2 divis. 2 divis. 2 divis.
Scale SA(5'2") ST(5'8") SC(6'3") SF10(7'0") SD10(9'0")
Notes to be set 54-88 54-88 54-88 54-88 54-88
Bubble Deflection 3 divis. 3 divis. 3 divis. 3 divis. 3 divis.
4, Install bass strings and set at zero bearing, Then adjust bearing
according to the following chart.
Scale SA(5'2") ST(5'8") SC(6'3") SF10(7'0") SD10(9'0")
Notes to be set 1-26 1-26 1-20 1-20 1-20
Bubble Deflection 1 divis. 1 divis. 1 divis. 1 divis. 1 divis
5. Retune piano to A-440 pitch.
CONCLUSION:
1. Bearing adjustments should only be made when the piano is maintained
under proper climatic conditions. (Humidity 35% - 45% with temperature 70 -
75)
2. The procedure and bearing gage must be applied in the order established.
3. A bearing value, previously set, cannot be rechecked because the
accumulated force of all strings on the bridges will lower the soundboard
and reduce the settings which were originally set.
4. Pianos equipped with the vertical (Acu-Just) hitch pins are designed to
function with a minimum positive bearing at the bridges, compared with other
pianos with string rests and angled hitch pins.
*Hand written note at bottom: 1 div. = .005" shim thickness with a Baldwin
Rocker Gage.
------------------ Page 2 -----------------------------
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, 1997
Baldwin Gauge | Lowell Gauge
------------------------------|-----------------------------
Bubble Degrees Bearing | Bubble Degrees Bearing
------------------------------|-----------------------------
0.5 0.14167 0.0025 | 0.5 0.08333 0.0015
1.0 0.28333 0.005 | 1.0 0.16667 0.003
1.5 0.42499 0.0075 | 1.5 0.25 0.0045
2.0 0.56666 0.01 | 2.0 0.33333 0.006
2.5 0.70832 0.0125 | 2.5 0.41667 0.0075
3.0 0.84999 0.015 | 3.0 0.5 0.009
3.5 0.99165 0.0175 | 3.5 0.58333 0.0105
4.0 1.13332 0.02 | 4.0 0.66667 0.012
4.5 1.27499 0.0225 | 4.5 0.75 0.0135
5.0 1.41665 0.025 | 5.0 0.83333 0.015
5.5 1.55832 0.0275 | 5.5 0.91667 0.0165
6.0 1.69998 0.03 | 6.0 1. 0.018
6.5 1.84165 0.0325 | 6.5 1.08333 0.0195
7.0 1.98331 0.035 | 7.0 1.16667 0.021
7.5 2.12497 0.0375 | 7.5 1.25 0.0225
8.0 2.26664 0.04 | 8.0 1.33333 0.024
8.5 2.40831 0.0425 | 8.5 1.41667 0.0255
9.0 2.54997 0.045 | 9.0 1.5 0.027
9.5 2.69163 0.0475 | 9.5 1.58333 0.0285
10.0 2.8333 0.05 | 10.0 1.66667 0.03
10.5 2.97497 0.0525 | 10.5 1.75 0.0315
11.0 3.11663 0.055 | 11.0 1.83333 0.033
11.5 3.25829 0.0575 | 11.5 1.91667 0.0345
12.0 3.39996 0.06 | 12.0 2. 0.036
12.5 3.54163 0.0625 | 12.5 2.08333 0.0375
13.0 3.68329 0.065 | 13.0 2.16667 0.039
13.5 3.82496 0.0675 | 13.5 2.25 0.0405
14.0 3.96662 0.07 | 14.0 2.33333 0.042
14.5 4.10829 0.0725 | 14.5 2.41667 0.0435
15.0 4.24995 0.075 | 15.0 2.5 0.045
15.5 4.39162 0.0775 | 15.5 2.58333 0.0465
16.0 4.53328 0.08 | 16.0 2.66667 0.048
Ron
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