GDT:Perpendicularity
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| Symbol | Perpendicularity |
|---|---|
| Type | Orientation |
| Category | Orientation |
| Standard | ASME Y14.5 |
| Author | Admin |
| Datums | Primary datum required |
| Modifiers | Diameter for cylindrical FOS; ST where allowed; material condition modifiers per feature type |
| Tolerance zone | Two perpendicular planes (planar) or a cylindrical zone (axis/feature of size) oriented 90 degrees to the datum |
| Image | GDT-Perpendicularity.svg |
| Common mistakes | Missing datum reference; using the datum feature as the toleranced feature; missing diameter on cylindrical FOS |
| Related | F4:Perpendicularity Validation |
Summary
Perpendicularity controls the orientation of a surface or axis relative to a datum at 90 degrees.
Definition
For planar features, the tolerance zone is two perpendicular planes oriented to the datum. For axes or cylindrical features of size, the zone is a cylinder oriented perpendicular to the datum.
When to use it
Use perpendicularity to keep a surface or axis orthogonal to a datum reference, such as a mounting face to a base plane or a bore axis to a datum axis.
Examples
Example: Planar surface perpendicular to datum A
Perpendicularity applied to a face with datum A as the reference.
Example: Cylindrical feature of size perpendicular to datum A
Perpendicularity applied to a hole axis with the diameter modifier.
Common mistakes
- Missing the primary datum reference.
- Applying perpendicularity to the same feature as the datum.
- Omitting the diameter modifier for cylindrical features of size.