Hex Nuts, also called Finished Hex Nuts, are made of low carbon, medium carbon, and alloy materials generally used with standard bolts. Hex nuts that are Galvanized have to be tapped oversize to allow for the extra thickness of the plating.
Heavy Hex Nuts
Heavy Hex Nuts are larger and thicker than standard hex nuts and are generally used for higher strength bolts with larger diameters.
2H Hex Nuts
2H Hex Nuts are medium carbon nuts that have been quenched and tempered.
Slotted nuts have slots formed in the head that align with holes in a bolt to allow use of a cotter pin so as to lock the nut in place.
Flange nuts have a larger base allowing for more surface area when attaching to material.
Lock Nut is a nut that resists loosening under vibration and torque. These come in a variety of designs but nylon lock nuts are the most common used today.
Acorn Cap Nuts
Acorn Cap Nuts are used when a stud or bolt end would be exposed and could cause safety issues or create a poor finished look.
Jam nuts are thinner than standard Hex Nuts and have two standard purposes. They can be used to lock a standard nut in place or sometimes are used for leveling.
Coupling nuts are generally used to attach two threaded rods or pipes together.