DIN 70852 Round Slotted Nut

The round slotted nut to DIN 70852 is a special type of fastener that differs from standard hardware in its design features. The side of the nut has several notches (slots) — from 4 to 8, depending on the size of the part: the larger the diameter of the fastener, the greater the number of notches.

Design features

This design makes assembly and disassembly of the connection easier. A slotted nut tightens faster and more reliably than standard equivalents. For this reason, these fasteners are widely used, for example, in the manufacture of automotive systems, including on the shafts of rotating components.

Slotted nuts weigh less than standard nuts, which reduces the overall weight of the structure — in mechanical engineering this affects the dynamic performance of the vehicle.

Another design feature is the chamfer, a small bevel on the face of the fastener. Some nuts have it, others don’t. It has no effect on installation or performance; the chamfer simply gives the nut a neater appearance.

Materials and coatings

Slotted nuts are made from materials with sufficient strength:

• metal alloys with high corrosion resistance;
• carbon steel grades 20, 35 and 40;
• alloy steel compositions;
• brass grade L63.

Some slotted nut models are produced with an anti-corrosion coating: zinc, cadmium chrome, or phosphate oil. The coating protects the fastener from environmental exposure and extends its service life.

Installation of slotted nuts

Due to the unusual shape of the slotted nut, a standard wrench is not suitable for installation. A special wrench is used, which resembles a can opener in appearance.

It has a semicircular tip with a small projection that fits into the slot and turns the nut in the required direction. The installation process is simple: this wrench is easier and faster to use than a standard one, and the connection made with a slotted nut turns out reliable.