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″.

Dynabrade 57763 - 6" (152 mm) Dia. Vacuum Gear-Driven Disc Pad, Vinyl-Face
Dynabrade 02054 4" Type 27 Guard 
