For zero setting of inside micrometers, three points internal micrometers and bore gages.
Deviation is the difference between the ordered size and the size marked on the setting ring when supplied.
For example, the ordered size is .2”, the size marked on the setting ring when supplied may be .20008″.
setting ring when supplied may be .20008″.

Insize ISV-RV, SIDE VIEW VIDEOSCOPE (RIGID), 6928640323423
Norton 66254497067 - 2" X 1/4" 100 - 150 Grit Medium Grade Aluminum Oxide Vortex Rapid Blend Blue TR Non-Woven Abrasive Disc, 25 Each
Dynabrade 11684 Dynabelter Contact Arm Assembly 4" DIA X 5/8" W., 40 Duro Serrated 