Lowell Gauge

[Ron Nossaman]

To whom it may confuse,

I rebuilt a Baldwin SF last winter which was my first Accu-just system
rebuild. To make life easier, I bought the Lowell downbearing gauge.
Following Baldwin's procedure (Tech Sheet TS039D) everything went very
smoothly. The piano sounded great. I remained smug and secure in the
knowledge that I had this sucker under control until I had to reestablish
the bearing on a seven year old 'L', under warranty, to try to improve tone
quality in the octave six area. This is when I ran into the problem of
translating the bubble graduations of the Lowell gauge into degrees. 

The bubble vial is graduated in groups of four marks. One would assume that
each graduation was either a degree, or a quarter of a degree (15') with the
bigger marks at every fourth being full degrees. Not so. Looking through
both the documentation that came with the gauge, and the information from
Baldwin, I found nothing telling me the graduation increment of the gauge in
degrees! Are all the degree of deflection figures being passed about based
on guess, or are they a mis-translation of the gauge readings? With these
disturbing thoughts in mind, I went out in the shop to do what I have to do
altogether too damned frequently in this business; get my own answers by
empirical observation.

I clamped the blade of my combination square (protractor head) in the bench
vise and zeroed it so the foot was parallel with the blade. Then I placed
the Lowell gauge on the foot and leveled it between two major graduations at
one end. Then I rotated the foot of the square until the bubble centered
between major graduations at the other end of the vial and read the
resulting angle off the protractor. Guess what, four major graduations on
the gauge equates to three degrees on the protractor. At sixteen minor
divisions to three degrees, each minor division on the Lowell gauge
represents .1875 degrees. That's 3/16 of a degree, or 11' 15". Each major
division, therefore, would equal .75 degrees, or 3/4 of a degree, or 45' 0". 
There you have it, gang. That ought to give your grasp of reality a kick in
the slats that will cascade back through all the measurements that you've
associated with this gauge through the years. You're welcome, no charge. 

I would appreciate everyone with one of these gauges and a combination
square with the protractor head to do this for themselves by way of
verification. This is such a weird graduation increment, I'm wondering if
they are all like this, or Tom's supply house snuck something strange in on
him. In any case, why isn't this information in the tech sheet that comes
with the gauge????????? Why haven't I seen it mentioned anywhere else??????????



 Ron Nossaman