NUT TYPES Acorn Blind tapped hex nuts with an acorn-shaped, peaked cap. Keep the end of the bolt or other threaded fastener from protruding to protect the threads, prevent snags, or stop the nut from threading down too far. Captive Also known as insert nuts, captive nuts help provide load-bearing threads in soft or thin materials. Simply press into a drilled or punched hole; knurled end cuts into the material and resists torque. Coupling Elongated nuts are tapped from each side so threads meet in the middle, rather than entirely through in the same direction. Connect two threaded rods, studs, or fasteners end-to-end. Flexible Top One-piece general-purpose locknuts have a flexible slotted section that expands to keep assemblies intact under impact, shock, or vibration. Reusable. Hex General-purpose hexagonal nuts for use with nonlocking applications on male threaded parts. These are the most commonly used nuts in assemblies. Jam Used as a second nut forced against the main nut to bind threads and prevent loosening. Prevent one nut from moving in the direction of the other without turning both nuts.

Locknuts Lock onto threaded bolts or rods to prevent rotation or loosening. Often require significant torque to turn—more than can be generated by most mechanical vibrations and other stresses. Minimal reusability. Spring Reusable nuts provide the correct amount of spring tension without damaging surfaces, eliminating the need for lockwashers and spanners. Thumb Knurled tops allow easy hand tightening, even when wet or greasy or in tight locations. T-Nuts Nuts with prongs on one side that lock into wood. Often used for fastening metal to wood. Weld Tab base nuts are used when working in confined spaces or when welding to thinner metals. Round base nuts are ideal as appliance levelers. Hex base nuts allow for rapid installation into holes prior to welding. Wing One-piece, round, threaded nuts with wing lugs for ease of manual assembly. Especially suited to applications where frequent removal, replacement, or adjustment is required.