Round Nuts

Round nuts are fasteners with an internal thread in the bore and slots on the outer surface. They are manufactured to GOST or DIN.

Application

Round slotted nuts are widely used in mechanical engineering. They are most often installed on a shaft to secure a bearing. The shape of the part prevents shaft runout and vibration during rotation.

Installation is performed with a special wrench: its lugs engage the slots of the nut, allowing the threaded connection to be tightened securely. The wrench is selected according to the fastener diameter — a wrench of the wrong size will not allow the connection to be tightened.

To prevent self-loosening, the nut is installed together with locking washers. The outer surface of the washers has tabs that engage the slots of the nut and prevent it from unscrewing. The number of slots on the outer side depends on the nut’s diameter.

Standards compliance

Nuts are manufactured to GOST 11871-88. The European equivalents of the standard are DIN 981 and DIN 1804. The standard defines the following parameters:

• Size.
• Diameter and thread pitch.
• Height.
• Weight.
• Material of manufacture.

The fasteners can be made of steel, stainless steel or brass. Steel parts can be manufactured with electroplating.

Types

Depending on the application, several types of fasteners are produced:

• With end slot. DIN 546 covers round nuts with a slot on the end face, used to secure the fastener.
• With holes. DIN 1816 covers fasteners with through holes in the side surfaces — these are used to prevent self-loosening with pins.
• With knurling. DIN 466 and 467 cover nuts with knurling on the outer surface, intended for hand tightening. The knurling prevents slipping.

Slotted nuts provide a secure threaded connection. Tightening is performed by hand or with a special wrench.