304 stainless steel flange nut M3/M5/M6/M16/M20

A flanged nut is a nut with a wide flange at one end that acts as an integral washer. This serves to distribute the pressure of the nut across the part being fastened, reducing the chance of damage to the part and making it less likely to loosen due to uneven fastening surfaces. These nuts are mostly hexagonal in shape and are made of hardened steel, usually zinc plated.

In many cases the flange is fixed and turns with the nut. The flanges may be serrated to provide a locking action. The serrations are angled so that the nut does not turn in the direction to loosen the nut. Due to the serrations, they cannot be used with washers or on scratched surfaces. The serrations help prevent the vibration of the nut from moving the fastener, thereby maintaining nut retention.

Flange nuts sometimes feature a swivel flange, which helps create a more stable structure without affecting the finished product like serrated flange nuts do. Swivel flange nuts are primarily used for joining wood and plastic. Sometimes both faces of the nut are serrated, allowing either side to lock.

Self-aligning nuts have a convex spherical flange that mates with a concave dish washer to allow the nut to tighten on surfaces that are not perpendicular to the nut.