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″.

Dynabrade 78424 4-1/2" Dia. x 3/8" Medium DynaBrite Surface Conditioning Disc, 25/pack
Dynabrade 78127 3" Dia. Medium NWN VT DynaBrite Locking-Type Disc, 25/pack
Dynabrade 53270 7" (180 mm) Dia. Right-Angle Disc Sander
Dynabrade 53533 Cone or Plug Grinder (Triple Extension)
Insize 1179-1000, DIGITAL RTJ RING GROOVE CALIPER, inside diameter of RTJ ring groove .6-40"/15-1000mm, outside diameter of RTJ ring groove 1.2-40"/30-1000mm, 6928640394409 