What is the meaning of Runout in GD&T callouts? what is circular and Total runout ? How is it inspected?
Runout geometric control is generally applied to surfaces which undergo rotation like shafts, hub , wheels etc.
There are two types
Here is a callout of a circular runout on a stepped shaft.
The primary datum feature of size is the smaller step of the shaft and the large step of the shaft is being controlled with respect to its runout within a tolerance zone of 0.1
What is the definition of the tolerance zone ?
Here is circular runout applied on perpendicular to axis surfaces.
The tolerance zone shape changes here , it is a set of concentric circles with a width of 0.1 based on the end flat face which is being controlled.
The inspection procedure remains the same , that the dial gauge indicator is brough into contact with surface and set to zero , then the total indicator movement reading is taken if its below 0.1 mm then part is acceptable in circular runout.
Same drawing with total runout applied:
Tolerance zone for total runout is concentric cylinders spaced with a value of 0.1 .
Circular runout vs total runout:
Example of application of runout:
Runout vs cylindricity?
Total Runout is a composite geometric control which controls both Cylindricity, Concentricity (position) and orientation of axis.
A reason why Runout is more commonly used for rotating cylindrical surfaces as compared to fundamental form controls like cylindricity.
When is runout used?
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Categories: : GD & Tolerancing