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 is "Cross-recessed pan head tapping screws". GB/T 845 is the Chinese national adoption of the same document.
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
GB/T 845 does not divide cross flat-head knurled self-tapping screws into product grades. Tolerances are given as limits on the individual dimensions in the table.
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.
Custom manufacturing · Made to drawing
Need a screw to this standard in a non-standard size?
Parts built to GB T 845 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
