This part of ISO 4759 pecifies a election of tolerance for bolts,crew ,tuds and nuts with ISO metric threads and with product grade A,B and C and for tapping crew with product grade A.
NOTE The product grade refer to the size of the tolerances where grade A i the most precise and grade C i the least precise.
The tolerance ,except tolerances for threads, are selected
from the system of limits and fits specified in ISO 286-1 and
ISO 286-2.The tolerance for metric threads are taken from the series of tolerance classes specified in ISO 965-3.The tolerance for tapping screw thread are covered in ISO 1478.
The tolerance of form and position are specified and indicated in accordance with ISO 1101, ISO 8015 and ISO 2692.
The tolerance specified in this part of ISO 4759 applyto fasteners prior to coating unless otherwise specified.See also ISO 4042.
Deviations from the tolerances specified in this part of ISO 4759 are only permitted in product standards where there are valid technical reasons.In cases where there is a difference between the tolerance requirements in this part of ISO 4759 and the product standard, the product standard takes precedence.
It is recommended that these tolerance also be used for non-standard fasteners.
Dimensions and tolerance given in this part of ISO 4759 are in millimetres.