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Bushings and Plain Bearings - Tolerances

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Wrapped Bushings Tolerances

It is not possible to accurately measure the external and internal diameters of a wrapped bushing in its free condition. In the free state, a wrapped bushing will not be perfectly cylindrical. The bushing will conform to the housing when the split is tightly closed. For this reason the OD & ID of a wrapped bushing can only be checked with special gauges and test equipment.

Below is an example on how to determine the bushing’s ID & OD tolerances with respect to the mating shaft and housing tolerances after installation:

Wrappd Bushing Tolerances

The chart and diagram shows that after installation this bushing will have a total OD tolerance of 0.030 mm. Also, the ID tolerance is 0.065 mm after installation.

Standard Bushings (non-wrapped) Tolerances

Standard bushing tolerances are specified on their respective dimension tables. For example:

Standard Bushings Tolerances

If a bushing with an 8 mm ID (d) and a 12 mm OD (D) is used, the ID (d) dimension specifies an F7 tolerance which corresponds to 13 µm / 28 µm. The OD (D) dimension specifies an m6 tolerance which corresponds to 7 µm / 18 µm.

Note:  Uppercase tolerances refer to different values from lowercase tolerances.

Download PDF of this information

 

Bushing Tolerances

Wrapped Bushings

 

It is not possible to accurately measure the external and internal diameters of a wrapped bushing in its free condition. In the free state, a wrapped bushing will not be perfectly cylindrical. The bushing will conform to the housing when the split is tightly closed. For this reason the OD & ID of a wrapped bushing can only be checked with special gauges and test equipment.

 

Below is an example on how to determine the bushing’s ID & OD tolerances with respect to the mating shaft and housing tolerances after installation:

 

Units: mm

 

The chart and diagram shows that after installation this bushing will have a total OD tolerance of 0.030 mm. Also, the ID tolerance is 0.065 mm after installation.

 

Standard Bushings (non-wrapped)

 

Standard bushing tolerances are specified on their respective dimension tables. For example:

 

 

Units: mm

 

If a bushing with an 8 mm ID (d) and a 12 mm OD (D) is used, the ID (d) dimension specifies an F7 tolerance which corresponds to 13 µm / 28 µm. The OD (D) dimension specifies an m6 tolerance which corresponds to 7 µm / 18 µm.

 

Note:  Uppercase tolerances refer to different values from lowercase tolerances.

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