Slotted set screws with cup point DIN 553 / ISO 7434-stainless A1 M3x18 mm

Stainless steel refers to alloyed or unalloyed steels that contain at least 10.5% chromium and less than 1.2% carbon. Colloquially, stainless steel is also referred to as stainless steel (NiRo), although not all stainless steel is the same as "stainless".

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.

Slotted screw drives are the oldest form of rotary drives for fastening screws. The Schltz is usually manufactured in a pressed or milled version. Because of its uneconomical processing method (slow, unwieldy), the slot is increasingly disappearing in favor of other drives (hexagon socket, cross slot, hexagon socket).

Grade 1.4305 is a sulphurised austenitic stainless steel of the A1 type. It is specifically intended for machining. Due to its high sulphur content of up to 0.35 per cent, this material has lower corrosion resistance than comparable stainless steels with a typical sulphur content of no more than 0.015 per cent. It is not suitable for use in non-oxidising acids and media or in chloride-containing environments (such as marine environments, etc.).

Only one number is used for nuts. This indicates up to which strength class of the screw the nut can be used. For example, you can use a nut strength class 12 with a screw 12.9, but not with a screw 14.9. 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.

A1: This grade of steel is specifically intended for machining. Owing to their high sulphur content, steels of this grade have lower corrosion resistance than equivalent steels with a normal sulphur content.