Armature Shafts: Gage Contact vs. Gage Line

Hello wingman1985,

On machine tool spindles, the gage line is sort of like a "theoretical sharp corner" or perfect starting point. ANSI taper spindles have a gage line dimension, 2.750" on a #50 taper, for example. All critical dimensions on a spindle, or mating toolholder, are measured from this location. Even though the spindle or toolholder may vary, they are measured in relation to this perfect "gage line". "Gage contact" I am not familiar with, but if I follow my imperfect logic I would guess that is where the gage line contacts its' mating part.

Hope this helps...