GB/T 22776-2008Tolerances and fits for timekeeping instruments - Tolerances of plastic parts (English PDF)

1 Scope

This standard specifies the timing devices with plastic parts tolerance.

This standard applies to the basic dimensions of 500mm smooth cylindrical plastic parts cooperation and non-cooperation dimensions.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent

Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research

Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 1801 limits and tolerances and mating with the choice (GB/T 1801-1999, eqv ISO 1829. 1975)

GB/T 1803 limits and with the size up to 18mm holes, shaft tolerance

3 Basic provisions

Hole 3.1 standard, the shaft tolerance zone are shown in Table 1 and Table 2.

4 Conditions

Plastic parts by molding after placing a certain time at room temperature environment, generally not less than 16h, in order to eliminate due process caused stress.

Inspection should be ± 2 °C temperature of 20 °C, relative humidity of 65% ± 5% of the conditions. Deviation from this condition should make the appropriate amendments.