General Tolerance Iso 2768-mk — Essential & Newest

If you are currently setting up a drawing or manufacturing run, tell me:

| Nominal Size Range (mm) | Tolerance ‘m’ (± mm) | | :--- | :--- | | 0.5 to 3 | 0.1 | | >3 to 6 | 0.1 | | >6 to 30 | 0.2 | | >30 to 120 | 0.3 | | >120 to 400 | 0.5 | | >400 to 1000 | 0.8 | | >1000 to 2000 | 1.2 |

Ensures that different machine shops interpret "standard accuracy" identically. Efficiency: Speeds up the CAD and inspection workflow.

Refers to ISO 2768-2 , covering geometrical tolerances (straightness, flatness, perpendicularity, and symmetry). Why Use ISO 2768-mK? general tolerance iso 2768-mk

While the "m" part dictates size, the "k" part dictates form and position. ISO 2768 Part 2 ensures that parts are straight, flat, and perpendicular enough to function correctly, even if specific Geometric Dimensioning and Tolerancing (GD&T) symbols are missing from the drawing. Straightness and Flatness

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.

saves you time and money. It tells your machinist: “I don’t need a micrometer for every single edge. Just machine it cleanly and consistently.” If you are currently setting up a drawing

To legally enforce these general tolerances, the standard must be specified explicitly inside or near the drawing title block. It should be written exactly as follows:

Used for structural components or parts where precision is not critical.

For parallelism , the tolerance equals the value of the size tolerance. For positional tolerances , the standard recommends using ISO 2768-2 only for "non-functional" features; otherwise, individually specify. Why Use ISO 2768-mK

To implement this on a blueprint, simply list the standard in your title block—for example: Any dimension left without an explicitly defined tolerance will automatically be governed by the tables above. If you are working on a specific blueprint, let me know:

Limits are based on the length of the longest surface line or diameter. Perpendicularity: Controls the 90-degree relationship between surfaces.

Circular run-out controls the variation of a surface during a full 360-degree rotation around a datum axis. For class K, the circular run-out tolerance is fixed at maximum, regardless of the size of the component. Why Use ISO 2768-mK in Engineering?

Part 2 establishes three tolerance classes: H, K, and L. The "K" designation represents the middle tier. 1. Straightness and Flatness