Limits for Ovality

This usually occurs as a result of the surface wearing, through friction or linear movement. Ovality can apply equally to holes and shafts.

Holes may be tested for ovality using such instruments as Go/No-Go gauges, internal micrometers or callipers. A shaft may be tested for ovality with the help of snap gauges, external callipers and micrometers. Both were previously discussed in the Tools topic of this course.

It is important to test for ovality of a shaft, before testing it for bow, as the results may suspect if bow is done first. Bow in a shaft can be determined in a workshop by utilising Vee blocks, a surface gauge and a DTI (in conjunction with a surface table).

FIGURE