Iso 2768-mh Tolerance Chart

The 'm' stands for Medium accuracy. This is the most common standard for general machining. It applies to linear dimensions (lengths, widths, heights) unless a specific tolerance is called out directly on the dimension.

The Chart at a Glance (ISO 2768-m):

| Nominal Dimension (mm) | Permissible Deviation (mm) | | :--- | :--- | | 0.5 up to 3 | ±0.1 | | Over 3 up to 6 | ±0.1 | | Over 6 up to 30 | ±0.2 | | Over 30 up to 120 | ±0.3 | | Over 120 up to 400 | ±0.5 | | Over 400 up to 1000 | ±0.8 | iso 2768-mh tolerance chart

Note: For dimensions below 0.5mm, the deviation is generally specified directly on the drawing.

Why use this? It saves clutter on the drawing. Instead of writing 30 ±0.2 on every single length, you simply rely on the title block standard. The 'm' stands for Medium accuracy

Tolerances in mm for nominal size ranges. Applies to external radii, chamfers, and linear dimensions (except broken edges).

| Nominal Size Range (mm) | Tolerance (mm) | |------------------------|----------------| | 0.5 up to 3 | ±0.1 | | >3 up to 6 | ±0.1 | | >6 up to 30 | ±0.2 | | >30 up to 120 | ±0.3 | | >120 up to 400 | ±0.5 | | >400 up to 1000 | ±0.8 | | >1000 up to 2000 | ±1.2 | | >2000 up to 4000 | ±2.0 | Tolerances in mm for nominal size ranges

Applies to dimensions where no individual tolerance is specified.

Tolerances for angles when no individual tolerance is given.

| Nominal Length of Shorter Side (mm) | Tolerance (degrees & minutes) | |--------------------------------------|-------------------------------| | up to 10 | ±1° | | >10 up to 50 | ±0°30' | | >50 up to 120 | ±0°20' | | >120 up to 400 | ±0°10' | | >400 | ±0°5' |

Also expressed as: Tolerance in mm/m = ±6 mm/m for class m.