Bolts always come with its nuts. But nuts also come in different shapes and sizes that will be confusing if you don’t know which one for which. So, again, knowing the basic nuts’ information is a good thing to do before choosing the one that you need. But, unlike bolts that have at least seven different types, nuts have way more.Cap NutsThe cap nut, also known as the acorn nut, gets its name from its shape. The nut has a domed top to prevent contact with the external thread.Castle NutsUsed with cotter pins to prevent loosening, a castellated nut, also called a castle or slotted nut, is a note with slots cut into the top. Used in low-torque applications such as holding a wheel bearing in place.Coupling NutsA coupling nut is a threaded fastener used for joining two male threads, most commonly threaded rod. The outside of the fastener is a hex so it can be driven with a wrench.Flange Serrated NutsA flange nut is a nut that has a wide flange at one end which acts as an integrated washer that does not move or spin. The serrated flange distributes the pressure of the nut over the part being secured and creates a locking action to prevent loosening.Hex Finish NutsHex finish nuts are used for fastening to a hex cap screw, socket cap screw or bolt. The most common nuts, hex finish nuts are hex shaped with internal threads and driven with a wrench.Hex Jam NutsA jam nut is often used when a nut needs to be locked in place without clamping to another object. Hex jam nuts are hex shaped with internal threads, but they are thinner than hex finish nuts.Heavy Hex NutsLarger, heavier, and thicker than a standard hex nut. Heavy hex nuts are hex shaped, internally threaded, and driven with a wrench. Often used with hex cap screws and carriage bolts.Hex Machine NutsA machine nut is hex shaped with internal threads. Smaller than a hex jam or hex finish nut, they are used with machine screws under 1/4″ diameter.Hex Machine Nuts Small PatternA machine nut is hex shaped with internal threads. Smaller than a hex jam or hex finish nut, they are used with machine screws under 1/4″ diameter.Keps-K Lock NutsAlso known as a keps nut, a k-nut or a washer nut, a keps-k lock nut has an attached free spinning lock washer. Keps nuts are designed to make assembly more convenient.Knurled Thumb NutsA knurled head thumb nut or thumb nut has a knurled outside surface rather than a hex, which facilitates tightening by hand. Often used in decorative finishes or applications.Nylon Hex Jam NutsA low-profile lock nut is hex shaped, internally threaded with a nylon insert. The nylon material prevents loosening from vibration and cross threads to stop the nut from backing off of the fastener.Nylon Insert Lock NutsA nylon insert lock nut is hex shaped, internally threaded with a nylon insert. The nylon material prevents loosening from vibration and cross threads to stop the nut from backing off of the fastener.Prevailing Torque Lock Nuts (Stover)Commonly known as stover nuts, prevailing torque lock nuts have chamfered corners and a conical top. The distortion in the top threads resists loosening from vibration. Also called one-way nuts, they can only be installed one way and are often used in high temperature applications because they are all metal with no nylon insert.Slotted Hex NutsSlotted hex nuts are nuts with portions cut out designed to be used with a cotter ping to create a locking mechanism. These nuts are similar to a castle nut but have a lower profile which sometimes makes them a better option.Square NutsA four-sided nut that may be flat or beveled on top. Square nuts provide a greater surface contact area which provides more resistance to loosening. Typically mated with square head bolts.Structural Heavy Hex NutsStructural hex nuts are comparable to finish nuts but are made to be thicker and much stronger. They are typically used in steel to steel structural connections.Shear NutsShear nuts are cone nuts with a hexagonal gripping point. They are designed with an intentional flaw to snap the hexagonal head off once the maximum torque is reached. Leaving behind a protective cone nut that cannot be easily removed.T-NutsA T-Nut is used to fasten wood, particle or composite board leaving a flush surface. A long thin body with a flange at one end resembles a T in profile. T-nuts often have 3 or 4 prongs that sink into the surface providing better retention.Tri-Groove NutsTri-groove security nuts have a tapered diameter making them difficult to grip with grabbing devices such as adjustable wrenches or pliers. These nuts require a special unconventional gripping device to install them making them more secure than a typical nut.Wing NutsWing nuts are threaded nuts with wings on each side of the body allowing for manual turning and installation. Easy hand assembly and used when the nut needs to be removed often.As we know, knowing this isn’t enough for you to fully understand which one is the best choice for you. That’s why we’re here to help you understand more about the nuts that are perfect for you. Hit us on our contact and drop your question. We will be happy to provide answers for everything you need.