Lock nuts DIN 1804W-5 steel unhardened and unpolished bright M10x1

DIN 1804 slotted nuts are round, unhardened, unground machine elements with four slots (= grooves) for the axial securing of shaft-hub connections, e.g. of gears on a shaft. They have a large internal diameter but a small external diameter. The internal thread is a metric fine thread. Slotted nuts are fitted using a hook spanner.

Only one number is used for nuts. This indicates up to which strength class of the screw you can use the nut. For example, you can use a nut strength class 5 with a screw 5.8, but not with a screw 8.8. If you use nuts with a strength class that is too low, there is a risk of the thread stripping. Higher ones can be used without hesitation, but should only be used if the load on the screw is above the yield point.

Steel is an iron-carbon alloy with a maximum carbon content of 2% by mass. The steels achieve their intended physical and mechanical properties through various hardening, annealing and tempering processes. It is also possible to harden the edge zone by surface hardening, case hardening or nitriding. Well-known steel grades are structural steels, free-machining steels, case-hardening steels, nitriding steels, tempering steels, tool steels and stainless steels.

The term plain indicates a completely untreated, merely oiled, smooth surface for all DIN and ISO screws such as wood screws, hexagon head screws, threaded rods, nuts and many types of washers.