What is ISO 2768?
ISO 2768 and derivative geometrical tolerance standards ISO 2768–mk and ISO 2768–fh are intended to simplify drawing specifications for mechanical tolerances. ISO 2768 is mainly for parts that are manufactured by way of machining or removal of materials. Variations on dimensions without tolerance values are according to ISO 2768, all tolerance limits are given in mm.

International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

General tolerance ISO 2768 does not specify where to use these tolerances. Tolerance class is defined as per design requirements and manufacturing capability. For example : for sheet metal parts ISO 2768–mk is used. And for machined components ISO 2768–fh can be used.

ISO 2768-2 : 1989, General tolerances — Part 2:

Geometrical tolerances for features without individual tolerance indications.

DIN ISO 2768 mk tolerances I do not have a full copy of the DIN but I do have some notes and a brief discription of how the tolerances are supposed to work but I still dont quite understand it. The parts are shafts and couplings and have to fit bearings so I know some of the tolerances are going to be plus and some are minus. Iso 2768 2 1989 general tolerances part 2 geometrical tolerances The three classes are identified through the use of the upper case letters H, K, or L after the ISO 7768 indication on the. This first edition of ISO 2768-1, together with ISO 2768-2: 1989, cancel and replace ISO 2768: 1973. ISO 2768 consists of the following parts, under the general title General tolerances: Part 1: Tolerances for linear and angular dimensions without individual tolerance indications. General Tolerances to DIN ISO 2768 T1 and T2 The latest DIN standard sheet version applies to all parts made to DIN standards. Variations on dimensions without tolerance values are according to 'DIN ISO 2768-mk'. GENERAL TOLERANCES FOR LINEAR AND ANGULAR DIMENSIONS (DIN ISO 2768 T1).

ISO 8015 : 1985

Technical drawings — Fundamental tolerancing principle.

Variations on dimensions without tolerance values are according to ” ISO 2768″. All tolerance limits are given in mm.

ISO 2768 and derivative geometrical tolerance standards are intended to simplify drawing specifications for mechanical tolerances. ISO 2768 is mainly for parts that are manufactured by way of machining or removal of materials.

Linear Dimensions

Permissible deviations in mm for ranges in nominal lengths	f (fine)	Tolerance class designation (description)		v (very coarse)
	f (fine)	m (medium)	c (coarse)	v (very coarse)
0.5 up to 3	±0.05	±0.1	±0.2	–
over 3 up to 6	±0.05	±0.1	±0.3	±0.5
over 6 up to 30	±0.1	±0.2	±0.5	±1.0
over 30 up to 120	±0.15	±0.3	±0.8	±1.5
over 120 up to 400	±0.2	±0.5	±1.2	±2.5
over 400 up to 1000	±0.3	±0.8	±2.0	±4.0
over 1000 up to 2000	±0.5	±1.2	±3.0	±6.0
over 2000 up to 4000	–	±2.0	±4.0	±8.0

External Radius and Chamfer Heights

Permissible deviations in mm for ranges in nominal lengths	f (fine)	Tolerance class designation (description)		v (very coarse)
	f (fine)	m (middle)	c (coarse)	v (very coarse)
0.5 up to 3	±0.2	±0.2	±0.4	±0.4
over 3 up to 6	±0.5	±0.5	±1.0	±1.0
over 6	±1.0	±1.0	±2.0	±2.0

Angular Dimensions

Permissible deviations in degrees and minutes for ranges in nominal lengths	f (fine)	Tolerance class designation (description)		v (very coarse)
	f (fine)	m (middle)	c (coarse)	v (very coarse)
up to 10	±1º	±1º	±1º30′	±3º
over 10 up to 50	±0º30′	±0º30′	±1º	±2º
over 50 up to 120	±0º20′	±0º20′	±0º30′	±1º
over 120 up to 400	±0º10′	±0º10′	±0º15′	±0º30′
over 400	±0º5′	±0º5′	±0º10′

Iso 2768 Mk Tolerances