Looking For Anything Specific?

Header Ads

Permissible Deviations for Linear Dimensions (Except Broken Edges)

Are there any that require high precision? Share public link

Section C 10. Ø12 H7 explicit callout controls; ISO 2768 does not override an explicit tolerance. H7 defines specific limits (hole basis tolerance); general tolerance ignored for that dimension. 11. Not acceptable for precision fit; drawing must specify tolerances (e.g., shaft Ø19.98–20.00 and bore Ø20.02–20.05) or use fit designation (e.g., H7/g6) to guarantee 0.02–0.05 mm clearance. 12. Consequences: possible assembly interference or functional failure; actions: reject/ rework part or negotiate acceptable nonconformance and update drawing tolerance notes; implement supplier corrective action.

This part of the standard covers lengths, diameters, radii, and angles. The "m" (medium) class is the industry's "sweet spot," balancing functional accuracy with cost-effective manufacturing. Linear Dimension Tolerances (mm)

: Reduces drawing clutter by only requiring specific tolerances for high-precision "functional" areas. : Parts with tighter tolerances than "mK" (such as plus or minus

By including a simple note like "ISO 2768-mK" on the drawing, an engineer communicates a clear, globally understood set of rules. This standard defines acceptable ranges of deviation for everything from a part's length and width to the straightness of its surfaces and the accuracy of its angles, ensuring that parts are manufactured consistently and fit together as intended. Its primary goal is to simplify drawing indications and ensure the basic interchangeability of components.

The purpose of general tolerances is to define the permissible deviation for dimensions that are not individually indicated on the drawing. These tolerances represent the normal manufacturing accuracy achievable by standard workshop machinery.

The designation indicates a specific combination of tolerance classes:

: Governed by ISO 2768-2 , this covers geometric characteristics like flatness, straightness, and circular runout. Tolerance Tables for ISO 2768-mk

| Tolerance Grade | Linear Tolerance (mm) | Angular Tolerance (°) | | --- | --- | --- | | f (Fine) | ±0.05 to ±0.5 | ±0.05 to ±0.5 | | m (Medium) | ±0.1 to ±1.0 | ±0.1 to ±1.0 | | c (Coarse) | ±0.2 to ±2.0 | ±0.2 to ±2.0 | | v (Very Coarse) | ±0.5 to ±5.0 | ±0.5 to ±5.0 |