View source for GDT:Straightness

{{Author Credit
|author=[[User:Admin|Admin]]
}}

{{GDT Infobox
|symbol=Straightness
|type=Form
|category=Form
|standard=ASME Y14.5
|author=[[User:Admin|Admin]]
|datums=None
|modifiers=Diameter (feature of size), ST (statistical tolerance, where allowed)
|tolerance_zone=Two parallel lines (surface line element) or a cylindrical zone (axis/feature of size)
|image=<!-- TODO: add diagram file name -->
|mistakes=Using datums in the FCF; applying straightness to a pattern; missing diameter on a cylindrical feature
|related=[[F4:Straightness Validation]]
}}

== Summary ==
Straightness controls the form of a line element or the axis of a feature of size. It limits how far the element or axis can deviate from a perfect straight line.

== Definition ==
For a surface line element, the tolerance zone is two parallel lines separated by the tolerance value. For a feature of size, the tolerance zone is a cylindrical zone around the axis.

== When to use it ==
Use straightness when you need to control form without reference to datums, such as keeping a shaft straight or controlling a line element on a surface.

== Examples ==
{{GDT Example
|title=Surface line element straightness
|body=Straightness applied to a surface line element with no datum references.
}}

{{GDT Example
|title=Cylindrical feature of size straightness
|body=Straightness applied to a shaft axis using the diameter modifier.
}}

== Common mistakes ==
* Adding datum references to a straightness FCF.
* Applying straightness to a pattern.
* Omitting the diameter modifier for a cylindrical feature of size.

== Related pages ==
* [[F4:Straightness Validation]]

[[Category:GDT Reference]]
[[Category:Form]]