For cross flat-head knurled self-tapping screws, GB/T 845 is the governing document for the dimensions listed below. Mechanical and performance requirements for this part family are set by its own standards, not by the bolt and screw property-class documents.
GB/T 845 — Scope
GB/T 845 specifies the dimensional requirements for cross flat-head knurled self-tapping screws.
Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for cross flat-head knurled self-tapping screws are given as limits on the individual dimensions in the table rather than as a fastener product grade.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by GB/T 845
| Head form | Under-head feature | Material | Finish options | Substrate |
|---|---|---|---|---|
| cross-recess flat head | under-head knurling | carbon steel | zinc plating | wood |
| cross-recess flat head | under-head knurling | carbon steel | colour zinc plating | plastic |
| cross-recess flat head | under-head knurling | carbon steel | black oxide | thin plate |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Cross Flat-Head Knurled Self-Tapping Screws page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify GB/T 845
Choose GB/T 845 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for cross flat-head knurled self-tapping screws.
