
330 Quality Assurance
Always remember, “Shift Happens!” Therefore, to minimize the effects of
datum shift, particularly when the datum features have a large size toler-
ance, reference datums at RMB or decrease the range of the datum feature
size tolerance.
Coaxial Controls Overview
• Circular runout and total runout are two low cost checks that
quickly provide an indication of the coaxiality of the considered
feature on an RFS basis. This control may be ideal for rotating
parts.
• Position with the tolerance evaluated at MMC is ideal for parts that
must t together and typically are not rotating. If rotation or balance
is a consideration, the ...