Acorn nuts have a dome-like cap that gives a finished appearance and covers exposed threads. They are also known as cap nuts.
Allen nuts have internal threading on one end and an Allen socket on the other. Allen nuts may have smooth sides or may have knurled edges so they can be tightened by hand before switching to a wrench. Allen nuts may also be called allenuts or internal wrenching nuts.
Binding nuts have an attached free-spinning external-tooth lock washer, which helps them resist vibration when the teeth bite into the item’s surface. They are also called Kep or Kep-lock nuts.
Coupling nuts join pieces of threaded rod with other male connectors. They are also known as extension nuts and are used in spacing applications.
Eye nuts create a lifting eye for an existing bolt or stud. The lifting strength depends upon the size of the bolt and the item it is secured to.
Flange nuts have a fixed washer-like, protruding rim that distributes pressure of the nut over a larger area of the item being secured. This reduces the chance of the nut causing damage to the item.
Hex & machine screw nuts have six sides; they are the most common nut. There are hex nuts that meet military specifications. They also come in thick and heavy varieties to suit most applications.
Locknuts have a nylon insert that reduces vibration and prevents loosening. They are also called nylon insert locks.
Nut inserts are internally threaded, hollow rivets. They are knurled on the outside and will expand after they are installed, which helps them hold tightly in place. They are also known as nutserts and rivet nuts.
Panel nuts are used to mount electrical switches into panel cutouts. They are thin with wide holes. They are also known as dress nuts.
Self-clinching nuts have a knurled end that can be pressed into a punched or drilled hole using a pressure machine that locks the nut into place. They are also known as captive nuts.
T-slot nuts are designed to fit into the T-slots on machine tool tables.
Thumb nuts are knurled to ensure a strong hand grip and can be tightened or loosened without tools.
U-nuts are designed to be clipped to sheet metal. Each nut is designed to accommodate a small range of metal thickness.
Wing nuts have protruding arms, called wings, which allow the nut to be turned easily without using tools, quickly installed, and frequently adjusted.