Full threaded rods are used in many different construction applications. The rods can be installed in existing concrete slabs and used as epoxy anchors. Short studs can be used coupled to another fastener to extend its length. All thread can also be used as fast alternatives to anchor rods, used for pipe flange connections, and used as double arming bolts in the pole line industry. There are many other construction applications not mentioned here in which all thread rod or fully threaded studs are used. Black-oxide steel screws are mildly corrosion resistant in dry environments. Zinc-plated steel screws resist corrosion in wet environments. Black ultra-corrosion-resistant-coated steel screws resist chemicals and withstand 1,000 hours of salt spray.Coarse threads are the industry standard; choose these screws if you don’t know the threads per inch. Fine and extra-fine threads are closely spaced to prevent loosening from vibration; the finer the thread, the better the resistance.Grade 2 bolts tend to be used in construction for joining wood components. Grade 4.8 bolts are used in small engines. Grade 8.8 10.9 or 12.9 bolts provide high tensile strength. One advantage bolts fasteners have over welds or rivets is that they allow for easy disassembly for repairs and maintenance.