These codes can be used by machinists or engineers to quickly identify the upper and lower size limits for either the hole or shaft. This Standard is used as an international standard for linear dimension tolerances.įor example, in H7/h6 (a commonly-used fit) H7 represents the tolerance range of the hole and h6 represents the tolerance range of the shaft. For a shaft of the same size, h6 would mean 10+00.009, which means the shaft may be as small as 0.009 mm smaller than the base dimension and 0 mm larger. H7/h6 is a very common standard tolerance which gives a tight fit.

2-1978) describes ISO standard of metric fits and limits for mating machine parts as approved for general engineering usage. For example: H7 (hole, tapped hole, or nut) and h7 (shaft or bolt). ISO Tolerance Systems For Limits And Fits American National Standard (ANSI B4. Fits are either based on the hole feature or the shaft feature. ex: 25 H11/c11 or separated with a dash ex: 25 H11-c11. ex: 25 H11 or 25 c11 A fit is defined by the basic size followed by the tolerance of each component. Limit dimensions are two dimensional values stacked on top of each other.Īdditionally, what is h11 tolerance? A feature tolerance is defined by the basic size followed by the tolerance designation. Three basic tolerances that occur most often on working drawings are: limit dimensions, unilateral, and bilateral tolerances. For a shaft of the same size, h6 would mean 10+0−0.009, which means the shaft may be as small as 0.009 mm smaller than the base dimension and 0 mm larger.Īlso, what are the 3 types of tolerances? H7/ h6 is a very common standard tolerance which gives a tight fit. International Tolerance grades For example: H7 (hole, tapped hole, or nut) and h7 (shaft or bolt).

H6 tolerance chart metric