GB/T 8-1988

GB/T 8-1988 specifies the dimensions, technical requirements, and marking of square head bolts classified as product grade C, which are characterized by larger tolerances and lower surface finish compared to higher grades. This standard is primarily applied in general mechanical assemblies, construction, and industrial equipment where precise alignment is not critical, such as in temporary fixtures, low-stress structural connections, or non-critical fastening applications. It is commonly used by manufacturers and procurement engineers for selecting cost-effective bolts in contexts where load-bearing requirements are minimal.