This part of GB/T 819 specifies the type dimensions, requirements and designation of countersunk flat head screws with cross recess and property class 4.8.
This part is applicable to countersunk flat head screws with type H or Z cross recess and with thread of M1.6~M10, property class of 4.8 and product grade of A.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies.
GB/T 5276 Fasteners; Bolts, Screws, Studs and Nuts; Symbols and Designations of Dimensions (GB/T 5276-2015, ISO 225:2010, MOD)
GB/T 5279 Countersunk Head Screws - Head Configuration and Gauging (GB/T 5279-1985, idt ISO 7721:1983)
GB/T 5279.2 Countersunk Flat Head Screws - Part 2: Penetration Depth of Cross Recesses (GB/T 5279.2-1997, idt ISO 7721-2:1990)
GB/T 5779.1 Fasteners - Surface Discontinuities - Bolts, Screws and Studs for General Requirements (GB/T 5779.1-2000, idt ISO 6157-1:1988)
GB/T 9145 General Purpose Metric Screw Threads - Limits of Sizes for the Screw Threads of Medium Quality and Preferable Plan (GB/T 9145-2003, ISO 965-2:1998, MOD)
GB/T 16938 Fasteners - General Requirements for Blots, Screws, Studs and Nuts (GB/T 16938-2008, ISO 8992:2005, IDT)
3 Dimensions
See Figure 1 and Table 1.
Symbols and descriptions of dimensions shall meet those specified in GB/T 5276.
4 Requirements and Reference Standards 5 Designation
