Carriage bolts with square nuts: 1) DIN603 , ... socket bolt.finish bright,zinc plated,hot-dip galvanized,mechanical plated ,nickel plated,blackgrades4.8,5. ... in producing many kinds of fasteners , such as bolts ,nuts, washers, screws, anchors and threaded rods. ... & Industrial AppliancesIndustrial Tools and MachineriesAutomotiveMedical EquipmentsMilitaryTelecommunications Carriage bolts with square nuts