During our working, we find many customers use DIN ISO 2768 standard as the machining tolerance of iron castings and steel castings.

Dandong Iron Casting Group inspect with ISO tolerance. Please check rough casting tolerance DIN ISO8062 and quality of Dandong Iron Casting Group for more.

The following are general tolerance of DIN ISO 2768.

Linear dimensions, External radius and chamfer heights, straightness and flatness, perpendicularity, symmetry, runout.

So we post DIN ISO 2768 standard here, for using it by ourself also for someone who need it.

We usually use m grade as the inspection standard of machining in Dandong Hengrui Foundry.

Regard the key dimensions or not very strict of dimensions, you should both indicate on drawings clearly, which helps suppliers to reduce the rate of defective goods and production costs. For our customers, it means improve the quality of products, also reduce sales prices, win more market share.

General tolerances for linear measures and level squares with four tolerance classes are useful for simplifying drawings. By choosing the tolerance class precision levels common in workshops should be taken into account.

If smaller tolerances are needed or bigger ones are more economical, then these tolerances are indicated next to the nominal size.

Table 1 – Permissible deviations for linear dimensions except for broken edges
(external radii and chemfer heights, see table 2)
Values in millimetres

For nominal sizes below 0.5 mm, the deviations shall be indicated adjacent to the relevant nominal sizes.

Table 2 – Permissible deviations for broken edges(external radii and chemfer heights)
Values in millimetres

Table 3 – Permissible deviations of angular dimensions

For nominal sizes below 0,5 mm the limit measures are to be indicated directly at the nominal measure. If general tolerances according to ISO 2768-1 are valid,
the following has to be inserted in the title box, i.e. for tolerance class medium.

ISO 2768 – m or general tolerance ISO 2768 – m

For new designs only the general tolerance according to DIN ISO 2768-1 should be valid. The limit measurements of the tolerance classes m and f of DIN ISO 2768-1 are identic with those of DIN 7168-1.