General Tolerances: Perpendicularity

Perpendicularity is covered by the general tolerances in ISO 2768-2:1989. It defines how much two surfaces, edges, or axes may deviate from a perfect 90° angle when no individual tolerance is specified.

General perpendicularity tolerances ensure that parts fit together without excessive angular misalignment while avoiding unnecessarily strict manufacturing requirements. This is important, for example, when an edge meets another surface, a bearing housing aligns with a shaft, or mounting holes must be drilled in line.

No separate perpendicularity indication is required on the drawing when general tolerances are used. It is sufficient to specify, for example, ISO 2768-mK on the drawing, in which case the permissible deviations specified by the standard also apply to perpendicularity.

General Tolerance Table: Perpendicularity

Tolerance class	Straightness and flatness tolerances for nominal length ranges
Designation	>		100	300	1000
	≤	100	300	1000	3000
H		0.2	0.3	0.4	0.5
K		0.4	0.6	0.8	1
L		0.6	1	1.5	2

The values in the table are given in millimeters (mm).