Standard Hex Bolts are for general hardware use where high strength is not recommended. The standard bolt is compatible with standard or Grade-5 nuts and washers of the same threading and finish. An alternative of using them with nuts is to place them directly into a threaded receptacle.
These Grade-5 Cap Screws are recommended for medium duty bolting applications. The Grade-5 bolt is compatible with Grade-5 and Grade-8 mating nuts and washers of the same thread pitch and diameter. An alternative for using them without nuts is to install them directly into a compatible internally threaded hole.