5. Tighten the hol ddown bolts and recheck the ind icator. If th e reading has c hanged, loosen
the three bolts a nd readjust. It ma y be necessary to o ver or undershoot t he desired reading
to allow for the effect of bol t tightening.
Correcting Parallel M is alignment

Preparation

— Attach the dial indicator t o one shaft or coupling hub and place the indicator
button on the O.D. of the othe r hub. The reach of the dial f r om one hub to the other should be
parallel to the shafts, and the dial button shaft shoul d point directly throu gh t he center of the
shaft on which it rests. Com p ress the plunger to about m id- p osition and set the dial at z er o.
Check the tightness of the dial button and the indicato r linkage by rotating the s haf t to which
the indicator is attache d 360 degrees. The dial sh oul d return to zero. Check for r ep eatability.
Check for runout by rotating the hub o n which the dial butt on rests 180 degree s. If the runout
exceeds .001 total indic a tor reading, the hub shoul d be removed and the shaft ch ec k ed . Shaft
runout must not exceed . 001 TIR.
The effect of hub runout can be eliminated by locati ng a po sition on the half coupli ng where
two readings 180 degree s apart read zero. Rotate th e coupling so that one zero poin t is at the
top and the o ther at the bot tom when checkin g for misalignme nt in elevation. Place the zero
Click here f or Figure 41 — Adjusting Angular Misalignment in Plan