Reading a dial gauge

[Mark Davidson]

"So if I put the plunger on the center of the bridge
with the two outer prongs resting on the front and
back segments respectively, does a reading of .018"
equal 1 degree?"

Yes, .018" is 1 degree.  And yes, you use 1" as the radius.

It's arcsin(.018" / 1").  But that's in radians, so you have to multiply 
by 180/pi to get degrees.  Comes out to 1.03 degrees.

Arcsin doesn't have much effect for small angles.You will get a good 
enough approximation if you just multiply .018 by 57.3.

-Mark